Thread: SBC 350 build

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Yep, I think the vortec heads with the COMP springs will be my best option. I will be sure to pull my rear-end cover and see what I have for gears. I'll be putting in new bearings all around in the bottom end of things and likely put in new pistons if the cylinder walls seem all good. You said not to run too much lift on my cam, what would you recommend for max lift I should run for a daily driver?
I was looking at the COMP XE274H
In lift-.490 lift
Ex. Lift-.490
In @.50-230
Ex. @.50-236
LS-110 degrees

Originally Posted by Bowtiepickups

Yep, I think the vortec heads with the COMP springs will be my best option. I will be sure to pull my rear-end cover and see what I have for gears. I'll be putting in new bearings all around in the bottom end of things and likely put in new pistons if the cylinder walls seem all good. You said not to run too much lift on my cam, what would you recommend for max lift I should run for a daily driver?
I was looking at the COMP XE274H
In lift-.490 lift
Ex. Lift-.490
In @.50-230
Ex. @.50-236
LS-110 degrees

Well, max lift will be determined by your valve springs and piston to valve clearance. I'm going to say it again. The camshaft is the LAST piece you buy for your build, after you have everything else lined out to work together.

One thing that I would not do, even if I were to use a flat tappet camshaft, is to use an extreme energy grind on a street motor build. The lift off the base circle of the cam on these grinds is the maximum rate of velocity that can be achieved with a flat tappet before the edge of the lifter digs into the side of the cam lobe. This is just stupid for a street motor. If you are in competition and an extreme energy grind will get you half a tenth, then the gamble might be worth it. Otherwise, use a cam with nice, easy ramps and let the valvetrain live in a kinder environment.

The following is my own approach to figuring out the relative work that a lobe is asked to do compared cam to cam. I don't know how scientific it is, but it makes sense to me in the context of how I use it. Math is black and white. There are no gray areas.
You can determine the relative tappet velocity of a grind by subtracting the 0.050" tappet lift duration from the advertised duration. I remember for years that Crane used a 56 degree difference on most of their cams. If you had a cam with 270 degrees advertised duration, then the 0.050" duration would be 214, for instance. Now, if we assume a symmetrical opening and closing lobe configuration for the sake of argument, that would mean that there would be 28 crankshaft degrees of tappet rise from the advertised point (usually about 0.006" up off the base circle of the lobe) to the 0.050" tappet lift point. So, we are lifting the tappet 0.044" in 28 crankshaft degrees. This would work out to a lift rate of 0.00157" per crankshaft degree.

Now, let's look at a cam with 270 advertised and 228 @0.050", a difference of 42 degrees. This would be a much more agressive camshaft lobe design. If we are using up the same 0.044" lift in only 21 degrees of crankshaft rotation, you can see that the rate of lift would be 0.00209" per crankshaft degree.

If you'll just think about it for a moment, you'll see that the cam lobe has to endure quite a lot more pressure to do more work in the same amount of time. If you plan to run one of these extreme energy grinds, then have the cam nitrided at the factory before they ship it and use the best lifters the grinder can offer. This is no job for "white box, no name lifters". Also, I would suggest backing up to the post where I listed all the things that can frag a flat tappet cam and pay attention there.

One other thing that I meant to address for you is the roller rocker. The value of a roller rocker is in the trunnion where it swivels on the rocker stud, not at the tip where is engages the valve stem tip. High speed filming of the valve action by a famous cam grinder, Racer Brown, showed that the roller tip is too small in diameter to generate a mechanical couple with the tip of the valve and that the roller just skids across the valve tip instead of rolling. As I said, the main advantage in a roller rocker is at the trunnion, not the tip. Do not be tempted to buy those fosdick Magnum rockers from Comp that use a conventional ball and socket at the trunnion and a roller tip. Comp got it bass-ackwards and those things should be against the law. They should have made a roller trunnion and a conventional tip if they really wanted to improve things. The other thing is, don't waste your money on 1.6 rockers for a small block Chevy. Use stock ratio 1.5's. In my opinion, the best value on the planet for roller rockers is the Scorpion units. You can get them in narrow body models to fit inside the L31 valve covers and they are made with the rail tip feature as well.

One other point. I made reference to using either the Edelbrock Performer RPM or the Weiand Stealth as the best manifolds for a street/strip motor. Tango has brought it to my attention that the Holley 300-36 is at least as good and after doing a little research on other forums, I understand it may even be better than the RPM or Stealth. Thanks Tango for the heads-up.

Oh as for pistons and freshening up, do the compression check, pull the heads and check cylinder walls. If they are decent you can probably do a basic hone job, new rings and bearings and let it go. If it's in bad shape you will need to take to a machine shop, rebuild, etc. As for pistons I am not an expert here but what I have in my 355 and what a lot of people seem to use are Speed Pro TRW flat tops. With 64cc Vortec heads and the correct head gasket thickness you will push about 9.6:1- 10:1 compression ratio and still be able to run on pump gas. I probably wouldn't run over 10:1 compression and wouldn't go under 9:1 for sure. Raising the compression some will help in gaining some power as well.
I am not an engine expert like some of the guys here so this is all I will say and this is all based on my opinion and what I have learned personally and from the guys here.
Good luck on the build!

Tech, on my TRW flat tops .030 over with 4 valve reliefs, it says 9.6:1 compression ratio with 64cc heads. Are you saying that is not true? I know that sometimes the specs on the directions or Summit are not correct and I have always thought this to be true with 64cc heads and also that would also assume that my deck has NOT been cut down any.

Originally Posted by FMXhellraiser

Tech, on my TRW flat tops .030 over with 4 valve reliefs, it says 9.6:1 compression ratio with 64cc heads. Are you saying that is not true? I know that sometimes the specs on the directions or Summit are not correct and I have always thought this to be true with 64cc heads and also that would also assume that my deck has NOT been cut down any.

the speed pro book shows were its parts number will be at given deck height. many pistons makers will move the C.H on a flat top if the cr needs to be some what close as the bigger bore gets the more swep volume more CR .with domes they adjust the CR by moving the dome .many do this so you need to deck to O or 010 to be were you want . I do it all the time

Originally Posted by FMXhellraiser

Tech, on my TRW flat tops .030 over with 4 valve reliefs, it says 9.6:1 compression ratio with 64cc heads. Are you saying that is not true? I know that sometimes the specs on the directions or Summit are not correct and I have always thought this to be true with 64cc heads and also that would also assume that my deck has NOT been cut down any.

If each of the reliefs is 3 cc's, then 4 of them would be 12 cc's, which would yield 9.6:1 with 64cc chambers on a 355.

as for a flat lifter cam solid or hyd i used many over the years and to say its oil or to much spring its alot more then that .so spin the wheel lay your bets down. as some one that send s engines out all over the USA and Canada .i have no controll over the oil or how many times will the guy dry crank a engine( I CAN NOT BE THERE) so if the guy can spend the $350 more for a retro fit roller... bare bones kit... i will do that.. if not. i take the time to get them understand just how critical break in on a new cam is with the right oil and thing still could go sideways . i never lost a cam on a SBC or potiacs fords amc and others over the years i done many flat cams over the years 32 years .two jobs still stick in my mind . did a magnum mopar roller engine. guy told me he crank it till the battery was dead and used a full can of starting fluid. he did not check the dist not plug in .i do not think a flat cam would of lived thru that guy? .i did tell him is was not happy with him. them i started up a 454 mark 5 engine for a guy i made sure it fired right up. a good friend built it very mild flat lifter cam engine he has been building engines and machining for 35 years less then a 100 miles cam was gone . i did the next rebuilt it with a rollercam. i built 6 engines for the guy over the years with the mark 5bbc. all his engines he wanted roller cams all but one bbc with a hyd flat lifter cam engine . i have rebuilds with flat cams with 100000. miles on them and rollers with over 200000. if i can get a guy to spend 350. more for a roller i will try .if i am building the engine and i getting the core i will get a block that came machined for a roller or can be set up with stock roller lifters they are less for a roller block. alot of warranty jobs in engine rebuilding comes from flat lifter cams that fail .customer have came to me after there flat lifter cams have failed .they looking for a job that will last so i lean to roller cams and after paying for another rebuild its not a hard sell . ones that do not i still build 6 or so engine a year with flat lifter cam s if i can not be there for break in .i talk with them abit i get to know if there getting over there head i try to line up someone that can help them fire up there new engine

Pat, what brand roller cam kits do you usually use? You have helped me in the past choose some cam styles and look at some head combos but I cannot remember if you use or prefer a certain brand or not?

Originally Posted by FMXhellraiser

Pat, what brand roller cam kits do you usually use? You have helped me in the past choose some cam styles and look at some head combos but I cannot remember if you use or prefer a certain brand or not?

on rollers i look at the numbers i do abit with ERSON they make me cams if i can not get a shelf grind i have used .howards. comps . isky .lunati .crane.crowers .but on the last ford i used a howards Big Nos cam numbers were wanted to see them and they had a core to grind the numbers on

Pat what would be your Cost for a Re-Man Short Block 355 with Hyper Cast Flat Tops rebuilt Rods Zero Decked HV oil Pump with retro Roller Camshaft and Lifters Roller Timing Set With Button and HD Cover ?

a much more critical rate of camshaft effects are the DECELERATION rates as the tappet nears the full open and also the closed area---one to elininate the valve from flying off rocker/pushrod/lifter combined diminsions and the other to eliminate bounce as the valve seats.

Originally Posted by jerry clayton

a much more critical rate of camshaft effects are the DECELERATION rates as the tappet nears the full open and also the closed area---one to elininate the valve from flying off rocker/pushrod/lifter combined diminsions and the other to eliminate bounce as the valve seats.

Thanks Jerry, I never addressed the other side of the lobe, just interested in making the point that an extreme energy grind will work the lobe and lifter harder than a gentler grind and is not particularly necessary on a street motor in today's world in my opinion.

If nobody brings up the downside of a more radical lobe profile, these youngsters are going to think it's a free lunch.

I agree 100%....

I was able to controll the urge to get carried away with the duration on the cam...unfortunatly I went with the extreme energy cam and now I wonder how long till the seats are gone or worse yet, the valve head is embedded in the top of the piston......Hopefully the rhodes lifters take some of the bite out of it.

Alright, so I'm thinking, I'm going to bite the bullet and do a complete rebuild of the motor reusing the block, crank and connecting rods. **Pistons are pending on what is in the block. ** I've decided I will bite for the extra few dollars and added security and go with a retro fit hydraulic roller cam. I'm going to do this engine right so i will be pulling it and borrowing my dad's 355 that's sitting on a stand in the shed while i build my 350. Nothing is set in stone of course but what i'm thinking so far is:
-new bearings all around
-D cup pistons- KB193
-Magnum Hydraulic Roller retro-fit (model, lift, duration to be determined when things are moving along a little down the road)
-Edelbrock Performer RPM Vortec intake
-Vortec heads with COMP beehive springs and 1.5 roller rockers
Should I get self aligning rockers or ones that use guide plates? The self aligning are only a couple bucks more than ones that use guide plates on summit.

Assuming my deck height is stock and stays the same with the KB pistons, I worked out a 9.57:1 compression ratio with 0.015 fel pro gaskets using summit's compression calculator.

While i rebuild the motor, I will be putting my transpak in my TH350 and 2500 stall converter (the 355 is putting out over 400hp and about 430ft/lb torque). Then I will do the gears in the rear end and hopefully my 350 will be ready to drop in once that is all done.
Thanks again, everybody for your posts. Everybody's opinions are appreciated.

Originally Posted by Bowtiepickups

I've decided I will bite for the extra few dollars and added security and go with a retro fit hydraulic roller cam.

I think you'll find that the best deal going on a retro roller will be from Howard's Cams, about 500 bucks for the cam and lifters. Most of their stuff is ground on a 112 degree lobe separation angle. You can install the centerline anywhere you want to though, when you are degreeing the cam in the block. Advancing it 2 or 4 degrees will add to the bottom end while detracting from top end performance. Retarding it 2 or 4 degrees will add to the top end and sacrifice some of the bottom end grunt. If you have to advance or retard more than 4 degrees to get where you want to be, then you have installed the wrong cam. Speaking of degreeing the cam, here is a tutorial that you should study until you know it by heart...
http://www.iskycams.com/camshaft.php

You might want to consider starting with a roller block. If you could find a good L31 short block with the roller lifters, dogbones and spider and the lifters were in good shape, you could be money ahead by not having to buy lifters, just buy the cam that will work for your combination and SCR. The added benefit would be the one-piece seal, as opposed to the two-piece seal in the earlier blocks like you have. If you don't do everything just right on assembly, the two-piece seal will leak and there's nothing worse than to get a motor together and running and find that you have a leak at the rear seal.

Originally Posted by Bowtiepickups

Should I get self aligning rockers or ones that use guide plates? The self aligning are only a couple bucks more than ones that use guide plates on summit.

The cheapest way to do it would be to pin the studs and use rail rockers. To use conventional rockers, you would have to remove the studs, mill down the pad on the head by the thickness of the guide plates, then drill and tap for screw-in studs with guide plates. Something has to keep the rocker tip centered over the valve stem tip, either a rail rocker or guide plates that keep the pushrod centered, which keeps the rocker centered. I don't think I would want to use rail rockers with a wild camshaft, but with what you are considering building (probably less than 0.525" valve lift), I would be ok with rails.

You'll have to determine if it is worth it to install roller rockers or use conventional stamped stockers. The advantages of rollers would be less friction generated, thus, less heat in the oil and the fact that they would be a true 1.5 ratio. Stockers will normally check less ratio than the engineers specified, sometimes as little as 1.4 according to some fellows, so you would not be getting the full valve lift that the camshaft was designed to produce. The downside is the cost and the fact that the rollers are not as durable as stamped steel rockers. Some fellows have experienced them coming apart and scattering little roller bearings throughout the motor. If you do run rollers, it's a good idea to epoxy some brass screen material over the oil return holes to catch the rollers before they go to the pan. Some might slip past and go down the pushrod holes, but hey, you do the best you can with what you have to work with. The screening can also catch shrapnel from fragged springs or retainers.

I searched around for the best price on Scorpions for you, seems like they have taken a giant leap in price since the last time I looked. Some ebay vendors are asking 300 bucks for a set. Anyway, the part number for a narrow-body (to fit inside the L31 valve cover), self-aligning, 1.5:1 ratio set of 16 is SCP1035. Mountain shows them as SCP1035-1 for 270 bucks. Click the blue oval that says "Update Price"....
http://www.mountainperformanceonline..._p/scp1035.htm

Originally Posted by Bowtiepickups

Assuming my deck height is stock and stays the same with the KB pistons, I worked out a 9.57:1 compression ratio with 0.015 fel pro gaskets using summit's compression calculator.

OK, first I want to make sure you learn the proper terminology. There is "block deck height", which is the measurment from the centerline of the main bearing bore to the flat deck of the block where the heads bolt on and is usually around 9.025" on a virgin block. Then there is "piston deck height", which is the measurement from the piston crown to the flat deck of the block where the heads bolt on with the piston at top dead center and will usually be from zero to 0.050", with an average of maybe 0.035". I know you will hear fellows say just "deck height" without specifying which one they mean and most of the time, in that case, they will be talking about the measurement from the centerline of the main bearing bore to the block deck. But I want to teach you properly, so whenever someone says "deck height", ask them whether they are talking about block deck height or piston deck height. They might look at you like you have two heads, but they are the ignorant ones if they don't know the difference. Now, as you know, ignorance can be cured by teaching and learning. On the other hand, stupidity goes all the way to the bone and is terminal.

To do the thing right, you would first align hone (or align bore if the register is way out of whack) the main bearing bore in the block. This will take out material between the centerline of the bearing bore and the centerline of the camshaft bore. If enough material is removed so that the timing chain will be sloppy, there are timing sets that are a little shorter to take up the slack. Then you would measure the block deck height. Normally, you will find that there is a fairly large discrepancy from one end of the block to the other. Sometimes the machinist at the factory did not get the register cleaned out of all the chips from the previous block and the block decks will be machined uphill/downhill. I personally have seen 0.014" on a 429 Ford block and I'm sure Pat McCarthy and Jerry Clayton have seen worse than that, as many engines as they have built. When you deck the block to bring it back to square, that's when you measure all the components (rod journal throw, rod length and piston compression height) in order to set your piston deck height according to the gasket you plan to use so you can set the squish between 0.035" and 0.045".

If you think about it, you can see where the intake manifold would not sit on the heads properly if the deck was tilted uphill/downhill. I think sometimes that is what makes an internal vacuum leak happen. This is where the outside of the intake manifold is pinched pretty well at the cylinder heads, but on the other end of the port, on the crankcase side where you can't see it, the gasket may not be squeezed and the intake ports are pulling in not only air from the carburetor, but also oily air from the crankcase. This can make you nuts if you don't know about it, because no amount of spraying a combustible material such as propane around the intake manifold will find an INTERNAL vacuum leak.

Now, another good reason to deck the block and maybe even take a skim cut on the heads is if you are going to use a shim gasket. You mentioned using a 0.015" gasket. That's a shim gasket, not a composition gasket. While a composition gasket will tolerate some wavy action on the deck and heads, a shim gasket is not as tolerant. Both the decks and the heads need to be pretty flat and smooth to insure that the motor won't spit out the shim. Just be aware.