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Hello all, I found a 355 with flat top pistons, healthy cam only specs I know on cam is .515 lift flat tappet. Motor was put in a s10 for drag strip. Made a a few passes and tranny broke. So they pulled motor out. Any way they have 305 truck heads on the engine. I want to put a milder cam in the engine. I have a set of vortec heads that I can have serviced and upgraded for the engine. Would the performace be worth the money? Or would you just do a cam swap? Thanks
 

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The L31 Vortec head uses a 64 cc chamber where the 305 is 59 perhaps even smaller depending on exactly which head casting it is. So the compression would come down a little which for a street engine might be useful with corner station gas.

The Vortec head breaths better and has a very efficient chamber, it depending on the cam and the head’s it is replacing delivers anywhere from 20 to as much as 60 horsepower and a similar torque increase.

As far as cam a milder cam might get you into detonation issues even with the larger chambered L31 head. We really need more numeric info on the existing head’s and the distance of the piston crown to head deck of the block, in other words has this been zero decked.

Bogie
 

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X2... plus would pull engine down and verify what you really have inside... piston design and compression height... measure cam base circle diameter and intake lobe and exhaust lobe diameters to compute actual cam lift and take a guess at durations...
305 truck heads may limit to less than 300 HP... Vortect heads allow 450 HP...
 

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You'll be replacing one of the worst flowing heads with the best production head chevy ever made for the SBC.

So, yes. Worth it.
 
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