454 2bolt hi-po question

Hello all, I am new here.. I had a good question that is irritating the ever living hell out of me. Hopefully I can get some good insight and knowledge from you more experienced mechanics.

I am currently rebuilding my 454, Now I checked the casting number through Chevy and the block casting came back as a 1969-1973 block year 454 engine.
I sent my block to a machine shop a few days ago and I had just recently called the shop back, and they told me I actually have a 396 bored .030 over... Now that cant be, because the pistons I pulled out where 454 pistons stamped with a .010 over bore... I was told that some 396 blocks were cast with the same casting number as the 454 in that year range.. But still the piston size and bores just don't add up. Any ideas on whats going on? I personally think the machine shop is trying to pull a quick one on me and swap my block out for some block they had sitting around for ever. Now I did stamp a mark that only I know into a certain place on the block.. But still, Any ideas on the piston and block??

sounds like its time to take your pistons to the machine shop and look for your secret mark---------

I smell a rat.....

.

Good one, Tech, yessindeedee.

Go ask to see your block and after they show it to you, tell them about your mark and watch their faces. I recovered a stolen manifold and set of carbs that way once; when I mentioned the marking I had done to the manifold and carb bases, the guy just about fainted.

I am going to the machine shop today. I have one of my pistons with me, and I will be doing some digging there. And yes I will be looking for mark.
Thank you Gents for responding, I'll keep you all updated.

double post due to slow internet...

So I checked the Casting number and the years are right, BUt what I got online through Chevy is wrong with what the Actual Book number has, SO it is a 396 bored.030 over too a 402. Its sad, I checked my mark and sure enough it was my block.
My heads on the other hand... Apparently they need to be reworked with the valve guides and seals..Because one head is loosing compression. But I never noticed an issue with power loss from that and that's more repair money I don't have. SO they will stay like that because I honestly don't think that is affecting my motor. I don't want to pull a pair from a yard as I like my Oval ports, and if I do pull a pair they will just have to be reworked anyways. Good news is they are 454 heads. Sooo time to save up some more money for an unexpected repair.. **)

If you have to rebuild your heads, consider buying a set of new aftermarket heads instead; you might find you will be money ahead that way, believe it or not.

why not check out having your heads rebuilt??

nothing great about 454 heads on a396/ 402 you will need i big dome on the 396/402 to get any CR. what many did was put the small chamber 396 heads on a 454 with a flat top pistons worked out very well

I have slight done pistons, and I would love to get new heads, or get my heads redone, but that costs money annnd I spent the last of mine ordering rings, and Bearings.

If the money's not there then the heads wait, but know in the back of your mind that they're costing you power and efficiency by leaking compression and start saving a few $$ as you can for new ones, and watch your CraigsList religiously. You never know when someone might turn some loose whey they need a few bucks quick.

Is your avatar picture recent? Cute kiddo!

Quote:

---

Originally Posted by Imbraced

I have slight done pistons, and I would love to get new heads, or get my heads redone, but that costs money annnd I spent the last of mine ordering rings, and Bearings.

---

396/402 most all had small dome on the 325 hp 396

What EXACTLY do you mean by losing compression??????head gasket leaking? valve leaking? cracks??


If your on a low $ budjet rebuild, have vales/seats refaced,maybe resurface deck surface---put it together and drive it---


Maybe post the casting numbers here and some pics of the piston or complete info as to numbers/manufacturer---seems like there's quite a difference in what you have compared to what you think you have----IE---you won't get a 454 piston into a 396 bore--------

Why not just sit back and wait on the heads??? Budget builds do not have to be done in a hurry, nor do high dollar builds! It usually works out far better to take your time, save up a few more $$$$$$, and do things correctly the first time!

even before that----there are items in this thread that don't fit together-----------straighten out what he has and if its all from the same engine---------

I know guys, I would love to get new valves, but the shop said it would be 350 bucks...Yeah no...I am just having them replace the valve seals for now, I know my valves aren't bent so I'm not worried about that. In fact I don't exactly know why they would be leaking compression, Maybe its my so called bad valve guides, but correct me if I'm wrong, Valve guides shouldn't all go bad at once on a head and leak that much compression..Im sticking to my original thoughts that the seals are too blame for now. I know a budget build should be done over time, but when you have a wife on your ass every day about this kinda stuff, You kinda want it done soon. Rspears: that picture is about 5 months old now, I just love it and my daughter ;) Jerry: I would love too but I had to stick into my budget of just getting the valve seals done up, I actually didn't think about getting the valves reseated though. Dave: I would love to wait, But they will go on for now. When I get the money again ill replace the heads with maybe a nice aluminum set, that will be awhile but hey it can be done.

Just to clarify, compression is going to have to leak by the valve seats, so having the valves & seats done, or maybe just lapping them in yourself with some compound and a cheap suction cup handle might help that issue, but if your valve guides are really bad then a valve or valves could be sloppy on the seat, too, but like you say it's likely not all of them at one time. The seals stop oil from leaking down the valve into the cylinder, generally seen as a big puff of blue/white smoke on startup due to oil leaking down and burning off on startup. You'll also suck oil at times when your vacuum is high, like idle and cruise, burning oil.

valve stems/guides need oil and gets it past the seals---the seals keep exhaust and inlet mixture out of the crank case---so seals must let SOME oil past or soon the guides/stems wear and then they don't do anything-------------------------------

Quote:

---

Originally Posted by jerry clayton

valve stems/guides need oil and gets it past the seals---the seals keep exhaust and inlet mixture out of the crank case---so seals must let SOME oil past or soon the guides/stems wear and then they don't do anything-------------------------------

---

Sorry Jerry, should have said "...keeps excessive oil from running down the valves...."

I'm going to re-seat the valves myself with the method rspears said, Its a lot cheaper to just do it myself sadly. I didn't notice smoke on first start up, but since my heads are in the shop I might as well get the valve seals replaced anyways, its cheap insurance. My pistons did have a bit of carbon build up but that's probably due to bad fuel, and one carburetor that needs a tune. And quite possibly just a small amount of oil leaking into the cylinders at night. But hey, doing the valves myself will be cheaper by about 315 dollars, Sooo that's the route I will take.

Hell, While I'm at it, I might get some blue marking ink, and a couple gaskets and port my heads properly on the intake and chamber, and possibly the exhaust ports too. The thought of doing that makes me nervous but it should be easy as long as I don't take off too much material. That should make the 402 breath better.. Any thoughts on that?

It's not hard to do some bowl blending and port match the intake to the heads. But unless you really know what you are doing, I would advise against going any further than just cleaning up the surfaces on the exhaust ports.

It's not as easy as it appears. If you have no experience at it, you're taking quite a risk.

Yea...On that note, I'll hold off on that as I do lack the knowledge and experience on that kind of stuff.
I just cant wait to get my engine in perfect running order.

here some things to think about from a guy that builds and machines engines every day from what i see . most guys think a port match gasket must happen. false engine will not care. if you do it wrong make something that ok to alot on money and time to fix a bad job. any thing under 500 hp it not realy worth much if you do it right . but i will go down this road some. you need to know where the intake fits on the block just hanging a gasket off the head or intake will get you close . when heads are bolted down you may need to cut intake or go thicker gasket to get your ports line up you my find that there some shift side to side from intake ports to dowles on block . many more.. not going to list them. i do a fair amount of intake and head work yesterday day i spent most of the day cutting a intake out as it mosty a custom cast intake made for race only heads to fit 3 brands of heads were port can be oval to rect port .my rule is it always better to have the intake a bit small better for fuel and air somewhat helps if you get any reversion wave up the intake port . as for blending and bowl work is a wast of time by hand .if you have never done it you have angles on valve and valve seats the 45 is what your engine will be may time race stuff can be face seat angle of 45. 55.50 the valve job should be done first then blend off the last angle this has alot to do with what machine and cutters or stones .to do the valve job with . seat /guide machine or with stones .when cutting a new raw head i use cutter that will let me form all the seat . lest angle of one to 5 angles at one shot so that is why i said bowling them is wast of your time if the machine shop has the machine to do this work .by hand u can hit the main seating face angle and rune the valve job. when i know it stock job i use 3 angle cutter and is a 45 angle i use a 3 angle like 30.45.65. cutter if guy wants more then stock or wants to do bowl work. i us one of my race cutter after i am done a can go deeper with a cutter that cuts the better part of the bowl .if
my last angle of cut .then there not much hand work to do. i finish the clean up if needed by hand blend work die grinder .i have seen heads turn to junk or at the lest a new valve by a guy with a die grinder. many times i hand roll my angles up to the bottom of the 45 face angle this job is very tricky at best one wrong move then seat will have to be re ground if stone or reface with cutter. for this fine work i used a mounted point on a die grinder i use MX/ craytex grit they rubber/grit mount points were you can do fine work and not worry about a sanding roll come loose and hitting the face of the 45. a word about lapping valves you must make sure there is no lapping grit on valve face and valve seat has you used it to seat angle s the grit hanging around it can screw up valve work i use a very fine grit .i some times lapping the valve only to see the lay out or if the finish some seats with the metal make up of the seat finish could be a bit better i use a very fine clover like 600 grit when done i wash valves then go over the face with a scrub pad gray 3m fine .with titaniums valves i do not lap i lay out the read out to were valve is hitting the valve seat with a marker with felt chisel tip like 1/4 tip

Anymore these years I usually only use lapping compound to make mark on valve that I sometimes backcut at more angles for increased flow at the earlier openings-

I just want to fix most of my compression loss, No point in rebuilding a engine if I don't fix the heads ya know? A simple valve lapping should help out a bit. I want every bit of horse power and torque out of a fresh rebuild as I can get.

Also when my buddy and I took the heads off, we measured the valve faces and I do have over sized valves, SO I think chances are the valve seat wasnt adjusted to the bigger valves so they may not be sitting correctly in the first place.

SO I think chances are--------------??????????????????????


You thought you had a 454, but it was a 396/402-----------


Losing compression??????????did you do a leak down check before you took it apart?????????
burnt/leakie valve???if so you have to do a valve job----------if the valve was leaking bad enough to disassemble an engine lapping valves ain't gonna cut it!!!!!!!!!!!!!If your guides are bad, the valve stems probably are worn also and seals ain't gonna help--------------------


You need to positively identify what you have, what the problem was (and where--if only one cylinder ---if all cylinders----)and choose the repair depth accordingly.


what size valves are in it and what diameter stems???? you can fix worn guides by knurling, using guide liners or replacing guides----------


if the loss is via worn rings----you need to hone and rering or maybe even bore/hone and replace pistons---


Any way, I believe that you are over your head in what you think you have and how to go about repairing it---


Get us some numbers and sizes (maybe pics of parts ) and Pat and I can suggest a route to take for repair, replace or to find a boat that needs an anchor---------

Welcome to CHR Imbraced;

I’ve been reading this thread with a bit of a smile on my face and purposely held off posting because Jerry and Pat have forgotten more about big block Chevy’s than I’ll ever know. While I’m not a big block guy, I am a pretty fair motor guy and I thought I’d throw in a few general comments/suggestions based on my observation’s.
1. Buy a book on big block Chevy engines and read it cover-to-cover. Suggestion:
How to Rebuild Chevy 366, 396, 400, 402, 427, 454 Big-Block Engines
2. Repeat step 1 several times.

Take the time to write out what your long-term goal is for this engine. Determine what needs to be done and then take the time and spend the money to do it right. I can’t tell you the number of times I’ve heard about (and sometimes helped) folks who do the minimum required and end up really disappointed. In my industry, there is a well-known old adage, “The demands of the service and the importance of the job are never so great that we cannot take the time to do it correctly.” It sounds like your block is being prepped at the machine shop and that’s a good thing. At the very least, have the it decked and the mains bored to make sure the reciprocating mass will be square within the block. Also have them install your cam bearings as I’ll bet you haven’t done such before and it does take a skilled hand and special tools to accomplish correctly.

You’re all over the place with the heads. You haven’t explained how you determined that you were losing compression and as has been stated by others, valve seals are not the problem. The little I do know about big blocks tell me that the 781's and the 049 heads (last 3 digits casting numbers) are pretty decent oval port heads. They’re probably fine for making 500 plus horsepower - especially if you truly have 2.19/1.88 valves. I am a bit concerned with some of your statements, i.e., “Also when my buddy and I took the heads off, we measured the valve faces and I do have over sized valves, SO I think chances are the valve seat wasn’t adjusted to the bigger valves so they may not be sitting correctly in the first place.” If the heads were originally equipped with 2.06/1.72 and larger valves were installed without cutting the seats the engine would have been a scrap heap as soon as you tried to start it as in all likelihood there would be all kinds of collision going on inside the combustion chamber.

My two cents also says listen to Pat about matching ports. I’ve seen some real botch jobs when people take a grinder and try to do this by hand. At this level, you’ll never see any benefit from any porting work you may attempt. I’d really recommend you save some money and have your heads done correctly by a competent machinist. You’ll be sorry if you try and work around this by hand lapping the valves as this can cause more problems if not done correctly.

Stan Weiss has a web site with all the information you’ll ever need about heads and how they flow:
Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software

I would suggest that you perhaps, start fresh with us by taking pictures of what you have and providing numbers for the block and heads as well as telling us about what you have for intake, exhaust, cam, transmission, read end and oh yeah – what kind of vehicle is this engine pulling around? On one hand you say, “…I want every bit of horse power and torque out of a fresh rebuild as I can get.” But you also want to stay on the low-down where the money is concerned. These are mutually-exclusive targets. It costs money to build a good engine and believe me when I say if you can’t afford to do it correctly, just wait until you have to do it over.

We’re pretty knowledgeable here and the two guys I mentioned above have built literally hundreds of big blocks ranging from stump-pullers for trucks to national champion dragsters. Listen to them especially.

Regards,
Glenn

I really appreciat the posts, SO dont get me wrong. Im still new too old engines and this is still a steep learning curve for me. Although I am not uneducated about them, for lack of better words. I am going to assemble the block tonight and throughout this weekend, I will take pictures and measurements of my valves.
I did not see that any of my valves were burnt, Just the normal carbon build up. My cylinder walls have been honed correctly by the shop I am getting my work done at. I am replacing/have replaced all seals, bearings, and freeze plugs. My piston rings are also replaced with cast rings for a better fit and seal. I am in non way restoring my engine to stop configuration. I know my heads are 454 heads per the casting numbers, I will get pics and numbers posted later on that.
My engine will be going back into my 79 camaro RS, I have a 10 bolt rear end. My transmission is a turbo350 with a Hurst duel gate shifter. I do plan on, in the future..maybe next tax season or two, to upgrade to a turbo400, holly 700cfm carb,( I'm running a holly 650 atm),and a forged crank.
I do have a cast crank for it right now that has been ground too 20/20 under, polished like a mirror, and re-chamferd.
My connecting rods are the stock rods but they are all in perfect but not new condition. My pistons, I personally cleaned, Although I cant tell if they are cast or forged. But I'm leaning towards cast.
I'm not looking for serious horsepower, but 400 would suffice just fine as this will be my day to day driver.
But like I said, and like requested I will take and post pictures.

I do appreciate all your responses once again and I would rather learn from the pro's then learn by my own mistakes.

Oops forgot to answer a question. The shop did a compression check on one of my heads and said it had no compression. The person didnt really tell me how or why accept that my valve guides where bad..I'm pretty sure valve guides are NOT a 350+ dollar job. And I'm sure that it wouldn't just be an issue on just one head.

Attachment 61659Attachment 61660Attachment 61661Attachment 61662Attachment 61663

So I had the valve springs replaced with new ones because my old springs where worn out pretty bad, and the valve seals replaced too.