Thread: A SBC build

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So does anyone care to look at what I am building and tell me if it looks OK? My SJ 327 block is built, bored 40 with .120 domes and everything was balanced. I am looking at the combo kit that already has dyno data, but they were built on a 350 base. Will this kit work the same on my 327?

Holley Street Dominator intake, Sq bore,As. holley Cyl Head Aluminum 68 cc
Intake Runner Volume (cc): 184cc
Exhaust Port Shape: Square Standard Plug Style: Straight
Intake 2.020 in.Exh1.600 in.
Intake Valve Angle: 20
Lunati cam with 235°/240° duration at .050, .490/.490 in. lift, and 112° lobe separation. $1,690. comes with head bolts and no gaskets.

OR
This kit did not give the details on the cam but is prob. close to the above kit.
edelbrock heads
64 CNC Machined Combustion Chamber: Intake 170cc
Intake Valve Diameter (in): 2.020 in.
Exhaust Valve Diameter (in): 1.600 in.
$1,590. comes with gaskets and no head bolts

eathier kit? or somthing totally different? Will be going in a 68 camaro with T400trans also have to decide on gears and converter size. Will drive it around but not on far off trips.

When you say it's a 350 base, do you mean the pistons are for a 350 or do refer to 350 hp?

Have you checked the DCR with both combinations? I would be concerned about the domed pistons with those head chamber sizes. The '63-'65 327 Corvettes used those type of pistons with 64cc heads, and the static compression ratio was 11.25:1. And I have a feeling that your cam does not have adequate overlap to bleed off enough compression to run pump gas. The DCR maximum for aluminum heads is 8.5 for 92 octane.

with domed pistons and that small of chambers, your are way out of the range for pump gas!!! Race gas is about $7.00 a gallon, makes for expensive cruising!!!!

I would look at either Edelbrock heads with 70cc chambers or Dart Pro 1's with 72cc chambers, or better yet, AFR 180 heads with 75cc chambers. See if they would bring your compression down enough so your DCR (dynamic compression ratio) is under 8.5. With the right cam you can run over 10.5:1 static compression as long as the intake valve closes late enough to create a satisfactory DCR.

Thats why i was asking, the "tech guy" at summit told me the head combos would work fine with pump gas, I have never tried figuring DCR or how a cam changes the numbers. By 350 base I meant the 350 CID with flat tops is what the combos had.....I didn't think the .120 domes would hurt me that bad with the 3.25" stroke, would 76 cc heads be better?

One of the kits, the tech guy said would put me at 9.8:1 cr
Guess I need to do some homework & get some help from you guys on figuring out what I need.
Is DCR easy to figure? how is it figured? or is there a thread on that already?

Here is the rebuild kit I have................

Product Line: Federal Mogul Premium Engine Rebuild Kits
Piston Material: Forged aluminum
Piston Style: .120 Dome
Piston Ring Facing Material: Moly
Piston and Ring Oversize (in): 0.040 in.

Notes: Approximate compression ratio 10.35:1 with a 64cc head.

First, let me say that that cam is so big for a 327 that it will be virtually unstreetable. I would recommend something comparable to a CompCams 270 Magnum (224/224, .470/.470). I ran that cam in a 327 and it had a nice lope, lots of power, and had decent street manners. I ran a DCR on your engine combination and with this cam, you would need 74 or 75cc combustion chambers--I calculated it with 75cc and the DCR was 8.35 which would be good for premium gas. I also calculated 72cc chambers (DCR=8.66) and 70cc chambers (DCR=9.11), both of which would require racing gas. While it is true that you could run a big cam so you could run smaller chambers, you would severely compromise drivability. I could not find the intake closing point figured at .006 valve timing for the Lunati Voodoo 60103 cam which would also be a good choice for you. Either way you would be pleased with the combination as long as you could use those AFR 75cc heads (AFR has the best flowing heads out there--they are not cheap but they are worth every penny). Your best option would be to use a kit with flat top pistons. It would give you a lot more choices for aluminum heads.

first, is the piston 0 decked?? and how far if it is?? a .120 dome is fine with the 68cc holly's or the 75cc afr. the 64cc eddys are pushing is. the cam is fine with the combo but the loss in stroke from the 350 to 327 will lose torque. if you can get 92-94 octane fuel then 10.5 will be fine. because the short block is already togather the worse thing could happen is it wont run on pump gas at full timing. if this happens and i'm 99.9% sure it wont then you will have to pull the heads and put a thicker head gasket on it. companys like flatout, sce, and others make head gaskets in .040, .050, .060, .070. so it's realy no big deal if it's off.it can be fixed. but like i said your fine if you stay 68cc or bigger on the chamber.

I don't want a "smaller" cam. I want the biggest cam I can run for my combo which I think would be the one I listed, I don't think a bigger cam than what i listed would help any. I also don't want my engine to have "street manners" I want my engine to be borderline streetable.It is not zero decked, the blocks head surface has not been touched.

with that said.... the cam is way to small and use the 64cc head with atleast a runner of 180cc. most out of the box 180cc heads start to crap out at .575-.600 lift. i would use a small roller cam not a flat tappet. push the compression to 11to1 with the right cam and you can add some octane booster yes it works. this is a engine i built for a guys vette last yr. the heads were afr 180cc, small roller cam, victor intake,750dp, comp was 10.82to1. rods eagle, crank stock forged. don't use a hv oil pump all they do is suck the oil out of the pan. run a 6-7qt pan so theres no oil problems. on the dyno most small block chevy will pull all the oil out of the pan with only a 5qt pan. the heads will have to be setup for a roller if you go that way. i used stud gridles for the valve train to. the engine made 415hp and 542hp on a 100shot of nos...good luck if you what the cam specs i will have to look them up. i think it was a small soild roller like 570lift and 258-260@.050duration...

Originally Posted by DennyW

I hope you have a blank check book when you start buying these parts. Anything over .500 lift, and it really costs in getting it to hold up in that motor.

Don't think i'll be going there!!! over 500 lift that is........The holley kit has the 490 lift and I think the Edel kit has about a 480.................Both combos are tested on a zero deck flat top 350 so it leads me to believe it will work for me............although one reply says It will not work and another say it will guess I'll have to see if anyone else has an input on if it will work. if not i'll just flip a coin and build it that away.

No blank check...............looking to spend >2K on heads/cam/intake and live with whatever power i can make................

.500 lift ???denny you messy with us!!! hell a new vette has more then .550 lift.

First, is the piston 0 decked?? and how far if it is?? a .120 dome is fine with the 68cc holly's or the 75cc afr. the 64cc eddys are pushing is. the cam is fine with the combo but the loss in stroke from the 350 to 327 will lose torque. if you can get 92-94 octane fuel then 10.5 will be fine. because the short block is already togather the worse thing could happen is it wont run on pump gas at full timing. if this happens and i'm 99.9% sure it wont then you will have to pull the heads and put a thicker head gasket on it. companys like flatout, sce, and others make head gaskets in .040, .050, .060, .070. so it's realy no big deal if it's off.it can be fixed. but like i said your fine if you stay 68cc or bigger on the chamber.

Trying to lower the compression with a thicker head gasket will undoubtedly make the problem worse as the quench will be totally screwed up. There should be .035-.045 quench if you are going to get the most efficient burn in the combustion chambers.

My this thread got big over the weekend!

It would be very helpful if people would post their goals for a particular vehicle when asking about engine builds. That way more accurate information can be passed along. It is a waste of time responding in good faith when it is not applicable. Thanks.