318 with 273 heads ?

[73-340]

i have a set of early 273 heads and 4bbl intake, 64-65. could i put this combo on a 318 with a mild cam and header and have a good result?


the reason for the question is because i have the combo for sale and the intake is only what buyers are wanting. to me if i just sell the intake the heads are no longer good to me. so i would like to sell the set or use them in some way. i have the 273 block, crank, heads and intake. no rods or pistons

 

[mtandrews]

the 273 has small 57 cc chambers so expect a compression jump which will affect octane requirements. Also the valves are small too, 1.78 intake and 1.50 exhaust which IMO is going backwards from a performance standpoint. Sometimes extra compression is good but compression with flow restriction is a detriment.

 

[mullinax95]

If you notice in this link the 273 and 318 heads have the same valve size. Most of them do anyways.

http://www.mymopar.com/headcastnumb.htm

 

[C130 Chief]

318 and 273 heads are basically the same port and valve wise. Early 273 heads had smaller chambers, so you will see a compression increase. With the factory 1.78/1.50 valves expect the heads to support 250-275 HP at best.

 

[b5cuda]

I swapped 273 closed chamber heads onto my 318 and liked the performance gain. My engine is .030 over 318, TQ 4bbl, Performer intake, electronic ignition, 340 cam and regular 318 x-manifolds.