BBC camshaft for propane

87_bigbadzuk · Mar 26, 2014

Buddy has a stock 454 out of a rv with 40k on it. We have a impco dual 425 propane kit to put on top of it. He wants to know if a different cam would give it a little more top end and if so which would you run? It will later be built with different hc pistons and heads to better suit the propane but for now should he do a cam swap or leave it? Also it will be hooked to a th400 np208 and 410 gears turning 38s. He needs to buy a stall convertor. This will be mainly a trail rig with possibly some street time during the Summer. Would a 2500 be too much.

altfuel1991 · Mar 27, 2014

My first question would be how much top end do you want vs how much bottom end are you ready to give up? With propane/trail rig you want a cam with a lot of lift but not a lot of duration so it builds torque starting early and continues throughout the entire rpm range. Are you going to be spinning this engine above 6500 rpm with stock rods and pistons? The "RV" cams offered by the cam grinders provide a good boost in torque and hp across the rpm scale. The "High Energy" series Comp Cams products do this as well.

It is your best bet to call one of the cam grinders and talk to one of their tech guys. They can match a cam to your application based on all the data you give them including the stall speed you are planning.

The photo on my post is of a 383 that produced over 500 lb.ft. torque from 1800 rpm to over 6500 rpm and would start simply by turning the starter switch. It had a unique idle and great throttle response.

blzrgb · Mar 27, 2014

Comp cam tech line. Memphis, TN.
1-800-999-0853

Pumpkin · Mar 27, 2014

a 262/270 comp 4x4 extreme cam (1400-5400) and you can use a stock convertor. 270/278 4x4 extreme cam (1600-5800) 2000+ stall.
Either one of these cams should be fine with the stock short block.