Hi again, looking for new head to wake the bird up. Im kind of worried though. i have a 350 that was rebuilt 4 or 5 years ago. Im wanting to put either 13,16,62, or the aluminum heads on it with roller rockers. Im worried that the top end will be too strong for the bottom end and will throw and rod or something. If they rebuilt it with stock replacement parts do you think it will hold up? and do u have to have the heads done to fit roller rockers? or will they fit without any work?
Any of those three casting numbers would be fine, but don't rule out #670, #12, #48, #061.
The only thing wrong with stock parts in the bottom end are the rod bolts. Nothing else in there is at risk with a 350 like the one you are trying to build. 1.5 ratio roller rockers can be added without any other changes or mods.
Just keep in mind that if you swap out the heads, you owe it to your car to give that 350 a little more cam, too.
Might want to consider a 1.6 roller rocker on the heads if you not planning on changing the cam. May also want to consider a MSD 6AL with a built in rev limmiter. Its not the power but the RPM that kill.
I would find a set of 62's to change on it. One thing about the 670's & 061's is they are the early big valve heads that utilizes a closed combustion chamber & a different valve angle. you would have to play close atention to the valve/piston clearances with any hi-perf cam. The 62 heads have a 75cc chamber & are open chamber heads, perfect for your engine. Will need to check valve clearance on the block to prevent bending a valve on the block near the piston bore. Keep the revs below 5800 rpm and you will be OK. If hi-perf rod bolts are in place , all the better. Don't get too wild on the cam but agree with Q, put some cam in it regardless. Stock intake & Q-jet for carb.
The 061 heads are actually hidden gems for a 350, IMHO.
First of all, they are open chamber heads with one of the best combustion chamber deisgns. The 1969/1970 Ram Air 4 chamber was patterned after the 061 chamber.
Second, they have press-in studs which is why most people pass them up assuming they are not high-performance heads.
They flow the same as any other D-Port, but they burn as good as Ram Air heads.
I stand corrected, lol!! I DO know that the 670's are a closed chamber. Also, you can convert the 061's press-in studs with screw-in studs with proper machining & parts. This would make them excellent heads as Q has stated to use on your 350. Good luck & let us know what you do & how it works out!
