273 commando HELP!!!

toolmanmike said
Agree. Magnum heads are pretty nice but not too much of an upgrade from stock 273 heads. The chambers/compression are almost the same and they do flow a bit better but if you are building a 1:1 273 you will need to do some head work. The Magnum rocker gear is strong enough but the shaft/adjustables are already there on stock heads. Don't discount stock 273 heads. I wish I would have flowed mine. If I ever take one off. I will get them flowed just to see what they will do. They have been milled .030 to minimum, polished chambers,Serdi seats, bronze guides, stock valves (damn) Gasket matched and ported. Gasket matched intake and stock manifolds as well. (exhaust is a bottle neck but I didn't want headers) I also didn't want to build a high performance 273. Just a good running stocker. Probably 250 horse as a guess.

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I agree the stock 273 head is more than enough for up to 300 ish hp, but magnum allows you to go over 300 hp and even if you don't care about more than 300 hp, you can get away with a lot less cam to reach whatever power level your looking for, more head flow and smaller cam is more streetable than larger cam and less head flow.

5.9L magnum heads makes about 300-320 hp with stock non performance cam, 360 LA heads makes about 250 hp with similar cam and 273/318 heads on a stock 360 LA would probably be about 200-220 hp . That should be a least a 100 hp difference from 273/318 heads to magnum. all with super mild cams.