273 head modding

[spstacman]

how big of vavles can i put in my 273 heads with out nocthing the block

and can you put magmun head on a 273

 

[65Vart]

1.78/1.50-inch , You can put bigger valves in i.e 2.02-inch intake valves , but they will be shrouded by the small cylinders and wont do you any good. A good set of 302 casting swirl port heads from a mid 80s 318 will go on and flow well but depending on the year of your cylinder heads you may need to swap your intake.

 

[spstacman]

i have the odd bolt heads , the car was a 2bbl i modded a sp2p intake to fit

 

[65Vart]

i have the odd bolt heads , the car was a 2bbl i modded a sp2p intake to fit

302s are what you want. Newer style intake will work with no mods (perfomer, etc).

 

[spstacman]

what about combustion chamber size

 

[IfItsGotWheels]

Your heads will take 1.88 & 1.60. Most other heads will reduce your compression.

 

[cudamark]

To answer your first question....a lot will depend on how far your bore your block. 2.02's won't fit a stock bore.....1.88's will. As previously mentioned, getting the valve too close the cylinder wall will negatively effect the flow. Better to have a little smaller valve. Any head swap should have the CC's checked so you can stay around the compression ratio you want.

 

[66dartgt]

You may want to consider a different intake as well. SP 2P's have extremely small runners that are intended for fuel economy. Switching to a late model performer or other type intake would be better and would show an immediate performance improvement.