Which heads for my combo?

Pistons are .053 in the hole which makes sense as to why a .039 head gasket and 53cc chamber with a true flat top piston yields 9:7:3 on my current combo.

I measured this the other day since I have the heads off now and one head is clear the problem. The valve is clean/greeen and the others are brown. I imagine the head is cracked because the gasket looks perfect. Maybe I should have the heads checked though so I know it is not the block. It would seem strange if the block was the problem though...


Anyways I just ordered 58CC AFR 185 Keith Craft CNC heads with Scorpian stud mounted Rockers. Should reall wake up with 308 compared to the iron GT40's...


I will however only see 9:1 compression or so. The shop I used to build my shortblock (in business 50+ years) said that I could get back some power I might loose from compression with timing adjustment. Keith Craft gave me the option of their CNC ported Brodix 5.0 or this AFR 185 for about the same price and the AFR has free shipping.

I will post a pic of my pistons soon but I am hoping not to have PtV issues since they are in the hole so much and the cam is .538 lift with 1.72 rocker.

Those heads will more than make up for that compression loss. Personally I would not shave them.

Originally Posted by iwantmore

Those heads will more than make up for that compression loss. Personally I would not shave them.

Yes I will keep them at 58cc.

I am using an inexpensive fedral mogul cast piston pictured below...Hopefully with my piston in the hole .053 and this head I will not have to cut the piston.


Federal Mogul Z273AP40 - Federal Mogul Cast Pistons - Overview - SummitRacing.com

Also...what kind of power should i excpect to make?

308
9:2 compression
AFR 185 CNC heads
224@.050 .532 lift 110lsa
Holley 670
Air Gap intake
1 5/8 long tube headers into 2.5 h pipe and dumped spin techs
mechanical distributor

c4 2100 stall
4.11 gears (not that is matters for power)

Wow those pistons are way down in the hole..I doubt you will be able to make up any extra power with timing because it will likely ping with much advance..My 306 had similar looking pistons .030 in the hole and it was very sensitive to timing . I had to run Premium 94 octane gas or it would ping despite being only 9:1 compression and a cam with lots of overlap....I could be wrong but I think that huge amount of quench is going to be a thorn in your side and limit your potential until its corrected..
What year is your block?...I assume it must be a 73-76 with the tall deck hieght?

It is a c8 coded 1968 block actually. It measures .05 in the hole. I always wondered why it pinged when I had 9:7 compression since I did not associate pinging with premium fuel with anything below 10:1.