Wyze

What's the difference in them???? I'm wondering mainly the heads, I got a guy telling me how much better the #5 heads are!!!!

joe_padavano

The differences in the heads are actually among the least significant of the differences. All 68-72 SBO heads have about the same 64cc chambers. CR was varied by changing the piston dish. 68-70 motors could be had with 9.0, 10.25, or 10.5 CR. The 71-72 motors were all low compression - about 8.5 - 9.0. The cam profiles were different. The 71-72 heads used induction hardened seats. Some of the later heads had deeper spring pockets for use with thicker valve rotators. This actually lets you run taller springs (less likely to coil bind at high lift) if you use normal retainers. Other than that, the motors were pretty much the same for those years.

stan 65 cutlass

good info. i have a 69 350 at home is there any way to tell what the cr is since there are three different ones ?

Wyze

Joe you must eat sleep & s%*t Olds!!!!lol
thanks for the info!!!


What can I do to beef up my 350 for under a $1000???

1969w3155

Camshaft. free flowing exhaust, stiffer gears.

Wyze

Ok it's a stock motor minus headers hooked to H pipes, performer rpm intake, and I believe a 650 Holley carb!!! (may be a 600)

Stiffer gears????

69Rman

1970pistons-1.jpg?t=1272475951
Here are some pics of the two pistons I have from two different 1970 350s
The one on the left came from a 2 barrel carbed 350, it has a deeper dish in it than all the high compression 350s from '68-'70.
The one on the right is the high compression 350 piston found in any of the high compression 350s from '68-'70, unless of course it is a W-31 engine, it has the flat-top, 10.5 compression pistons. I do not have any of them to show you.
Duane

1969w3155

If you are running the stock 2:56, 2:78, or 3:08's, than move up to 3:23's or 3:42's. If not a daily driver perhaps 3:90's.