My son has a standard 70 2 barrel carb Camaro. We are thinking about doing some upgrades. A set of 3.55 gears, he already has a RPM AIR GAP intake and 4 barrel Holley. We also plan on a comp cam XE268H cam. I did a search but can't find any info on the heads. Does anyone know the combustion chamber and valve sizes? Are these heads good enough for a mild build like we have planed? Will a set of Vortec heads work good with this combo? What is the combustion chamber size on the Vortec? Thanks MIKE

 

Had you not already purchased an intake I would have suggest the Vortec heads, but now you'd have to port match them, rather than buy an intake designed for the Vortec heads.
I would surely consider a set of 2.02 or 1.94 heads if you can get them. Your stock heads are probably only 1.70" and the larger combustion chanbers will further lower the compression ratio. These are pretty reasonable, and will work well with even a pretty hot engine build. Or just get a set of good aluminum heads, if your budget allows it.

 

You could remove your valve covers, get the casting numbers off them, and post them here to get a better evaluation of what you have. Almost 40 years is a long time for somebody to have replaced them.
And contrary to popular myth, a standard intake manifold will not work with Vortec heads unless a bit of welding and machining is done to them. The height of the runners are so different between them (Vortecs are a lot taller), that there is no matching gasket surface above the old style intake runners to seal against the Vortec heads. With that being said, the Vortecs are still a heck of a good iron head, and can be made even better with a little massaging. If you were able to find a decent set, it might make it worth while selling your intake manifold and buying the correct Vortec specific intake.
http://www.customclassictrucks.com/t...evy/index.html
http://www.chevyhiperformance.com/ho...458/index.html

 

Thanks for the info guys. This is a project we are planning for the spring. Right now the car is under a tarp and covered in snow so i can't get the head numbers. But when I can I'll post them. Thanks again.

 

I have one more question.
The L-65 is rated at 9.0:1 comression
The L-48 10.25
The Z-28 11.0:1

Im assumeing that the L-48 had smaller chamber heads than the L-65 but they both had the same dished pistons. And that the Z-28 Im assumeing had small chamber heads and different pistons, maybe flat tops. Am I correct?

 

No, that's not correct. In 1970 the 9:1 compression was a flat top with valve cuts in the top, the 10.25:1 and 11:1 were both domed pistons with the 10.25 having valve cuts too, and the Z28 11:1 not having them.
Both of the higher compression engines were equipped with heads that had slightly larger combustion chambers, while the lower compression engine actually had a smaller combustion chamber due to the flat top pistons. It also used the smaller valves.
The Camaro engines for 1970 were rated 250, 300, and 360 hp, with the 360 hp being the only engine to use the solid lifter cam.

 

Okay, so what cc heads will bring up the Compression on a 9.0:1 L-65 engine without changing the pistons? Thanks MIKE

 

Since that engine most likely has the smallest combustion chamber of all, there's not a head that will raise compression. However, you can have your heads checked and see if they can be milled .010" to lower the volume of the combustion chamber further. If they've already been milled this can still be done, but it's not reccommended, as it requires the intake to also be milled when you go over .010" mill. This is also the cheapest way to raise the compression ratio.

 

I'm going with THESE Summit Vortec heads. $309.10 per assembled head. Vortec heads are probably the best value in SBC iron heads. Even if you find a set from the bone yard and have them rebuilt they're still a great deal. Vortec heads out flow all other GM production iron SBC heads, including the original Chevy Bow Tie heads.

I'm going with a Edelbrock Performer EPS Vortec intake manifold. No sense messing around with a standard style intake manifold trying to make it work with Vortec heads. You'll spend more time and money then it's worth.

 

Yes, Vortec heads will work well, and they have the same old 1.94" valves of the early small block fueler heads, plus 74cc combustion chambers that will raise the compression. But they do have a couple drawbacks. They don't allow lifts over .470" without a lot of work, so no big cams can be used with these haeds. They also require a different intake, so if you bought that new intake you'll need to sell it and buy one for a Vortec head.
On the plus side they do create a better combustion flow pattern, so you might make up for the little 1.50" valves on the exhaust of a Vortec head. Looks like the Summit Vortec heads have an even smaller 67cc combustion chamber too.