Hey Guys,

I finally am looking forward to having my engine rebuild in my 84 T/A and I want to put a set of L31 Vortec's on it. I was going over this article Vortec Heads on 305 and I was wondering if anyone knows where I can find the actual specs that they milled the heads to? Thanks!

 

I recall (from ancient foggy memory) they shaved them down about .030" to get chamber size down to 58cc so that compression was unchanged from the stock 305 heads.

 

Typical for SBC heads is .005"-.006" per cc, so .030" is reasonable.

I'd recommend cutting less than that, cc'ing the chambers, then doing the final. But, you'd probably be safe with .030".

 

So if I get this right, it sounds like they just mill the bottom of the heads so they are shorter...thus bringing down the compression ratio... As this is pretty much my daily driver I'd like to stick around 9:1 or so to let me run on 87 Octane...

I was reading through the article again and it looks like they milled them down .045 then used a thin head gasket to get 10:1 compression...but that's too high to run anything but premium right?

 

Daily driver? Small camshaft?
I wouldn't get too caught up on milling the crap out of them then. Slightly lower CR isn't all that bad.

 

I will also be installing a Lunati Voodoo Cam and lifter kit, number LUN-60100LK from summit.

The stats on the cam from Summit are Duration @ .050 IN/EX: 207/213; Lift IN/EX: .437"/.454"; LSA / ICL: 112/108; RPM Range: idle-5000

Obviously I'll be replacing the springs as well and installing a set of roller rockers just for kicks. I'm hoping to get somewhere close to 300hp out of this build which isn't that far off from what carcraft got in theirs.

If I have any money left I may spring for a larger torque converter as well. B&M and TCI sell a few that look like they would fit my application fairly well.