Determining Static Compression and Valve Springs

[jgkurz]

Hi All,

I am helping a friend get his newly acquired 71 Ford Bronco running and need some advice. The engine is a seeming radical 302. We know very little about the engine but are convinced it needs to be de-tuned. When he bought it earlier this week it had a tunnel ram with dual 4 barrel Holleys, NOS, Victor Jr heads and a HUGE Crower solid cam. Something to the tune of .579 lift. It runs like total crap. We switched the tunnel ram out for a basic dual plane aluminum intake with a 600cfm 1850 Holley. We want to buy a new cam and lifters since the current cam is completely stupid for the street. I know what profile I want, but I am hesitating because I am not sure about the static compression. If it's 9.5:1 then that one cam, if it's 11:1 then I'd go with a different cam.

 

It's my understanding that a typical compression test won't help since I believe the current cam would affect the results. Any idea's?

 

 

Also, the valve springs are triple's? Should I remove one of the inner springs if I want to run a street hydraulic cam?

[74_5.0L_Z]

If it was my engine, then I would really have to find out what the bottom end consisted of. At the very least, I would pull one cylinder head and the oil pan. With the head off, I could get numbers off the piston. The numbers on the piston would give the manufacturers information on dome/dish volume. The same information is published for the cylinder head combustion chamber. Then with the head off, I'd measure the "in the hole" depth of the piston to the deck, and also get an exact value for the stroke. These days there are a lot of stroker 302s running around.

 

What are the specs on the old cam?

 

I am wanting something a bit bigger for mine. Currently, I have a Crower 15511 hydraulic roller.

[jgkurz]

Here's the cam that's in it right now. WAY overkill.

 

 

 

Like you suggest, we are planning to take a head off so we can identify the pistons and stroke. Thanks for the response.

 

-John