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Author Topic:   305 heads
Dirt Roller

Total posts: 21
posted June 10, 2002 11:18 PM
Can anybody tell me what I should expect to get performance-wise out of stock 305 heads on a 350/.040 over? How do they compare with 0462 dblhumps that I am used to running? Is there anything I should do to them besides pinning the studs? Will valve train geometry be the same? Trying to build a CHEAP claimer motor here--any help would be appreciated.
Oh yeah, track is medium banked 1/4 mile, I'm running about 6000 rpm with a 6.90 final.

Dirt Forum Racer

Total posts: 87
posted June 11, 2002 01:46 AM
What's the casting numbers on the 305 heads you are thinking about running? Some 305 heads are equipped with larger valves and have larger intake runners. In my opinion none of the 305 heads (without mods) will out perform a set of 462's (without mods). But maybe someone out there has done it.

Dirt Maniac

Total posts: 115
posted June 11, 2002 10:53 PM
the runners on 305 heads are a little smaller plus the biggest valves that im aware of from the factory are 1.84/1.5. you may get good torque but i think it will hurt your top end. you can cut them out for 1.94 valves but they get awful close to the side of the combustion chamber.

Dirt Freak

Total posts: 430
posted June 11, 2002 11:53 PM
You might also lose some rpm's I know when i switched from 305 heads to ported 462's there was a world of difference and I gained 200-300 rpms. I don't know if you will lose any or not

Dirt Roller

Total posts: 21
posted June 12, 2002 10:30 PM
Thanks for the info guys! Not sure what the casting number is, but there ain't nothing special about the heads--they're off a chevy 305 in a 79 olds cutlass--I'll have to check the valve size--but we are limited to a 500 cfm 2bbl carb anyway, so I suspect that the intake valve size won't be my limiting factor. I've had several guys tell me 305 heads are a cheap and easy way to raise compression--And like I said, I'm trying to get out cheap. I want to run up front with a motor I can afford to sell in a claim! That's why I don't want to run my 462's under this claimer rule!

[This message has been edited by dilbert (edited June 12, 2002).]

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