Hey guys. I have a 88 camaro with a carburated 350.. I bought the car a couple months ago as a project for me n my son's and put a posi and 4.10 gears in the rear end. Im tryingvto get some power out of it for racing once ina while but still want to be able to drive it on the street on weekends.I just bought a set of vortec 906 heads and had a valve job done and had them machined and z28 valve springs installed. There's so many different camshafts out there I'm just lost tho. Lol. The block is 3970010 bored .040 over, flat top pistons with 4 eyebrows in them, right now i have a 600 cfm edelbrock carb, 700r4 transmission, not sure about the converter but will probably upgrade it in the future, the guy I got it from said the trans was just rebuilt but I'm not sure. The machine shop guy recommended a Howards 112141-12 and said I could go as big as .550 lift but I don't think I want to go that big. Just thought I would see what kind of advice n help I could get on here. I appreciate any and all. Thank you.

 

The 906 heads are great heads, and make great power/torque under the curve. Ultimately though, they're not gonna flow on the high side what some of the big name aftermarket heads are gonna do. With those heads, the right cam, and that cube to carb cfm ratio, I think you'd have a beast of fun street car. Not sure how successful it'll be on the dyno or even with ET's at the track, but it'd be fun for sure.

I'm not an expert on how to cam a carbed car, so my "official advice" would be to talk to the guys over at Comp Cams or Lunati. They have quite the reputation for being very knowledgeable, plus they've both got some REAL nice cam lineups, as do some others. If I had to offer and "un-official" guess though, I'd say something similar to a GM Hotcam. Lower side of mid .500"s on lift, duration around 220 or 230.....

 

Since your machine shop guy said you're good to .550" lift, we'll assume he cut the valve guides down or set the heads up with a spring retainer package that permits lift over the stock Vortecs' ~.475" limit. Don't be afraid of lift. If the heads can handle .550, take advantage of it.
Unfortunately those "Z28" springs aren't going to support much of cam. They're going to be marginal even for a Hotcam.
What's your compression ratio? quench clearance (deck clearance + head gasket)? Those answers will help determine the cam type.

 

I'm not sure to be honest. Maybe you guys could help me figure that out too. All I have right now is feeler gauges n I tried to figure out piston to deck clearance n got .030? I ordered a felpro gasket I believe it was .032 compressed? I was going to get the .015 gasket but If I am wrong about the deck clearance I don't want the piston to smack the head? What do you suggest I do? N what would my compression ratio be? I really appreciate all the help doing this guys. It's my first rebuild so im just going with what I see n read online. Thanks.

 

The number on the Pistons is 345NP .040

 

Unfortunate that you have those pistons; they're "rebuilder" pistons that are .020" shorter than stock, and therefore sit an additional .020" down in the hole. If you have piston to deck clearance of .030", then obviously quite a bit was taken off the deck of the block.
What's the chamber cc of your heads?
Regardless, you'll need to run as thin of a head gasket as possible. You need to tighten up that quench, and get some compression back to prevent the engine from being a low-rpm dog. With good deck surfaces, definitely run a .015" gasket. .045" quench clearance is still larger than optimum. .032-.035" would be optimum.
Do some measurements and report back. Depending on CR and what you end up with for quench clearance, I'm already thinking the Hotcam is the most you will want to run.

 

Damn. Thats not what I wanted to hear. Lol. Specs say 64cc? but machine shop resurfaced them, I'm not sure how much they took off though... So I should probably get the .015 gasket? The deck doesnt look like its been cut at all... I don't want to have to start replacing pistons too. The wife is already about to bury me over this car. LOL. So I gotta make the best I can happen with the bottom end that I've got. Thanks again man. You guys are awesome.

 

I just measured deck clearance again n its .032... so if I get the .015 gasket what's the compression ratio with 64cc heads? Is it going to be a gutless dog unless I get the block decked or new pistons? I definently don't want to do all this n not have power like I'm hoping....

 

A neighbor of mine has these same pistons...... in his 385 SBC.
You have a .040" over 383 = 385 ci.
It is done the old school way using a turned down to 350 journals 400 crankshaft with 5.565" 400 rods.
You need to recalculate everything now, because if those Vortec heads have 64cc chambers, you now have more than a 10.5:1 static compression ratio.
If your heads are off the block, you can measure the stroke by the distance the piston travels - you should measure 3.75" if you have a 383/385.

EDIT: if I am wrong about this, then his 385 is actually a 350, .040" over.

Forget what I typed - I had a brain fart.

 

Not so bad then if clearance is .032". They DID deck the block quite a bit.
Your CR works out to 10.25:1.
The Comp XR270HR (218/224/110 on 106ICL) would work well. I'd run 1.6 roller rockers with it if the heads have been modified for the lift. 1.6's would give 528" I/.536" E lift.
That cam would have a stronger low and midrange than the Hotcam.
Hotcam wouldn't be a bad choice though if you can find one cheap. Get some degree bushings and install it at 106 ICL rather than the "drop in" 109 ICL.

 

If you go with at least a 3000 stall 9.5" torque converter, the XR276HR cam would be a good choice too. DCR would be 8.2:1.

Regardless, make sure you replace those valvesprings!

 

Awesome! Thank you guys. I'll probably use the original vortec rockers for now n probably upgrade them with new springs after this and a new converter. Are the original rockers 1.5? Also will the push rods that I took out of this motor work with the vortec heads? Really dumb question but what is DCR and why would it change with the cam? Thanks.

 

Hold on.....what cam are you thinking of running with those "original vortec rockers" ?
It'll have to be limited to a lift that doesn't cause stud interference with the length of the slot in the rockers.

The original rockers actually check out at something like a 1.45 ratio.

Don't just assume that the stock pushrods will work. With the deck milling that was done on the block, plus the lift profile of your new cam, you'd better check for proper pushrod length rather than just assume.

DCR is dynamic compression ratio. Instead of your full stroke of 3.48", it's a compression ratio calculation that uses the stroke length from intake valve closing to top dead center. For a given SCR (static compression ratio), a longer duration cam will give a lower DCR to ward off detonation at lower rpm's. But, you don't want anything lower than about 8.0 DCR to avoid a low rpm dog. When you get near 9.0 DCR, you start to get into detonation concerns on pump fuel. This is all generalized guidelines; a lot of engine characteristics play into it as well.

 

Jeez. See that's why Im glad I found this site. It really is like rocket science. I give u guys alot of respect for knowing all this stuff n putting it all together like that...
Guys at the machine shop were saying they haven't had good luck with comp n their lifters so I think n hoping I could go with the Lunati Voodoo 268? Then get a 2500 stall converter later n hopefully have atleast 350 hp? Lol. Maybe I'm just hoping for the sky. Here's the specs tho. Let me know what you think.
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• Advertised Duration (Int/Exh): 268/276
• Duration @ .050 (Int/Exh): 227/233
• Gross Valve Lift (Int/Exh): .489/.504
• LSA/ICL: 110/106
• Valve Lash (Int/Exh): Hyd/Hyd
• RPM Range: 1800-6200
• Includes: Cam & Lifters (#71817PR-16)

Part Number: 10120703LK
Previous Part Number: 60103LK

 

Is your engine the original in that '88 Camaro? If so, it's a roller cam. That 10120703 is a flat tappet cam.
If you want a Lunati roller cam, the best fit would be a 20080721. You'd just need to replace/shorten the dowel pin on the cam nose, since that cam comes with the longer version to drive the LT1/LT4 Optispark.

 

No its not the original motor. It is a 3970010 block with CMJ date code? I think its from '74 from the research Ive done. Which one would it be? Thank you much.

 

Ok, for flat tappet, that 10120703LK is a good choice.