Hello all, if I bore my 327 .030 and put in some 11.8 to 1 pistons, is there a cam I could use and run pump gas? I have the 461-1.94 heads,performer manifold,600 carb, fulllength headers,roller rockers,and 3.08 gears. thanks, 62 Rodent

Pray tell, why do you want to do that???

I'm not saying it can't be done, but why beat yourself over the head when the little motor can be made to run GREAT, (imho), on pump gas AND not go overboard on compression!!

Anyway, theory has it that you need the smallest chambered heads you can find and plane to min. combustion chamber size to achieve your wanted CR.

Next - true flat-top pistons with min. valve notch size and min. quench., like from .035" to .040".

The longest rod you can afford helps here, too as does only a 230 at .050" cam and smaller.

PHR did an article on how to do this but was only at, like 11.2 to 1 CR. on both SB's and BB's!!

I do know that the Fueling 454 small valved, figure-8 chambered, truck torque heads were successfully ran on a 502 at like 12.1 or so CR. using this same theory so it can be done AND THIS WAS ON 87 OCTANE CAT-PEE!!

The test was after 700 T at right at 3500 to 4000 rpm and I think they missed their goal by 30 T!! Small cam and small valves and all!!!

The Fueling Engineering 454 heads are really for duelie work trucks to beef up their midrange gooseneck trailer pulling capacity AND do great in that application from what I have read!!

pdq67

I've got the pistons #L2252AF,and every thing else,and was just wondering if I could make it all work. 62 Rodent

Mill off the top part of the domes to get the compression down where you need it. Simple operation for any skilled machinist.

-Mark.

Theoretically you could run on pump gas with the right cam. You'd need something like a crane f-300-2 to bleed off the compression. This would get your DCR down to 7.9. You'll need a cam that closes the intake valve at least 82 degrees ABDC to get below 8:1 DCR. The problem then is with this radical of a cam, you'll sacrifice the lower end and with 3.08 gears that's a problem. Why not get a different set of heads like a set of 441s with 76cc chambers?

You could, but it would run like crap IMHO.

-dnult

RPOL78 has a good point. Short stroke, high compression, high RPM engines need higher numerical rear gears. You will need to decide what you are going to build.

A mild low compression, low RPM 327 can work with those 3.08's but I doubt any hot rodder would make that selection. Not enough torque to make it worth the effort. The short stroke hot rod type engines are better suited to high RPM, high compression, and 3.73 or higher gears depending on the total combination IMHO.

The combination needs to match. smile.gif

-Mark.

Agree with all the above. Need much steeper gears, mill the domes and I'd look at other heads. The 461s work well on little motors, with medium perf cams. Flat tops would be better and you need a long rod, which will require different pistons or a shorter stroke crank if you insist on using the pistons you have.

Like the others said it could be done in theory with a big enough cam but with stock port heads and a mild gear it would be a total waste.

FWIW you would need 304* advertised duration on the intake with a 112* LSA and 4* advance to get an 8.0:1 DCR. Even more duration with a tighter lobe separation angle.

I'd find a way to lower your static compression ratio to 9.5-10.0:1, then you could use a smaller cam that is more apropriate for your gear and heads.

Thanks for all the replys everyone,I think I'll give up on that idea. 62 Rodent