View Full Version : Big Block Chevy guys

10-12-2004, 05:00 AM
Hey guys, I have a 402 I want to put a set of LS7 rect port heads on. I havent got the parts in my hand yet, but the owner was asking if we thought there would be a clearance problems with the smaller bore.

Needless to say I told him to be sure I neded to check it out, but does anyone know if its a sure thing either way?

Mostly for curiosity. Thanks in advance

10-14-2004, 10:14 AM
are you sure you want to put such a big pair of heads on a 396? I would opt for some oval ports, but the rectangles should bolt on just fine, take a head gasket and match it up.

10-14-2004, 06:10 PM
Its a 4.88 geared drag car. We need it to breathe a bit better. I was concerned of valve size with the smaller bore. I'll check everything when I get the parts here, but I was wondering if anyone had any known interference problems.

In Ford circles, you cant run a 2.25 intake on any FE other than a 427 due to bore size. Wasnt sure if the LS-7 heads were any bigger and the customer doesnt know what he has.

Thanks and I'll let you know what I find.

10-29-2004, 01:00 PM
i have a 396/402 block with AFR magnum 305 heads, they have 120 cc chambers and 2.25/1.88 valves i think and it clears, not sure what the sizes on the ls7 heads are though so this might not help.

10-29-2004, 04:04 PM
The chambers on my LS7 crate motor heads (steel) are 118cc with 2.19/1.88 valves. They should right up to the 396/402 block just fine, but as was mentioned I'd bring along a head gasket and make sure everything matches up.