273 commando

[muleskinner]

if I use 318 open chamber heads.
WWith10.5.1 popup pistons will I get a satisfactory result.

 

[273]

if I use 318 open chamber heads.
WWith10.5.1 popup pistons will I get a satisfactory result.

Depends on your definition of satisfactory, the commando is rated 10.5:1 but comes up short, open chambers will drop it some more, will it kill no, but you'll lose a bit.

 

[muleskinner]

Depends on your definition of satisfactory, the commando is rated 10.5:1 but comes up short, open chambers will drop it some more, will it kill no, but you'll lose a bit.

I plan on driving this car everyday weather permits.
I'm gonna use them put 340 size cam and 4bbl fi.
If it doesn't work I'll change it.
Thanks

Depends on your definition of satisfactory, the commando is rated 10.5:1 but comes up short, open chambers will drop it some more, will it kill no, but you'll lose a bit.

 

[OldmanRick]

Your going to have to measure everything to be sure where you end up compression wise. That may require altering the head gasket thickness to narrow it down. With a 340 style cam in the .220 to .225 at.050 range, i'd shoot for 9 to 9.25 comp with the iron heads so you can run a good amount of timing for whatever pump gas is available.

 

[OldmanRick]

@toolmanmike

This thread may be better in the small block section

 

[toolmanmike]

@toolmanmike

This thread may be better in the small block section

Got it. Thanks

 

[cudamark]

I'd CC the combustion chamber and heads to see what you have first. You also need to decide what fuel you plan to run so you have max performance vs cost, vs detonation.

 

[AJ/FormS]

IMO; bad combo, but hey, I've done worse.
Forget the 340 cam. Then maybe you can make something of it, if it doesn't break the pistons first.
With thge 340 cam, my guesses:
>Yur bottom-end is likely to be softer than a slanty up to 3500
>Power may not begin until 4000
>Heads done by 5000
>Rev's to 5500, if the valves don't float, but just howling.
Needs a 3500 stall and 3.91s
> stock 318 with a 4bbl, will blow it away in first gear with a 2800 and anything over 3.23s ............ and probably to 50 mph at least.
But-um gaskets are cheap.

Like I said forget that 340 cam on this combo.

 

[273]

@66fs is the 273 guy ask him for ideas on good workable combo.