Jolly Green

What camshafts you running and why? I asked Mondello Twister what they suggest and they told me a cam with a duration of 277/285 degrees. That seemed a lil high for a mostly street machine with Test N' Tune at the strip. I read that anything over 250 is generally for a dedicated dragster. What do you guys think?

88 coupe

Looks like the JM-3-4:

Lifts are: intake = .522" and exhaust = .542"
Advertised duration: Intake = 277° and exhaust = 285°
At .050" valve lift: intake = 230° and exhaust = 238°
Centers of the intake and exhaust lobes are 110° apart.

Your 250° would apply to the .050" number. Which, as you thought, is a bit large for most street applications.

Advertised figures are seldom accurate enough to be useful.

Norm

Olds64

Bob Gerometta suggests the following cam for a mild street car in his Engine Modification and Tuning Guide.

JM-22-25
266*/274* .512"/.523"

He suggests the following cam for factory modified cars.

402194
308*/308* .474"/.474"

The first cam is available from Mondello and the second is available from Supercars Unlimited. However, I know that Comp Cams makes a copy of the second cam because it was the cam that came stock in the late 60s Hurst Oldsmobiles.

88 coupe

Based on what? That he thinks the JM-22-25 is best for any 455 that is driven on the street? Not likely.

Because the Mondello tech line recommendation was based on information given by Jolly Green, by default it would be the better choice. That does not mean it would be his best choice.

But, that is not what was asked.



In my 431 inch, 3900 lb, drive anywhere, street rod.



11.9 seconds, in normal street trim.

With the same cam, but different heads, carb/intake, and rear gears, my 461 was in the mid 12s

My choice was the result of a consultation with my builder. For best results, I suggest you use the same approach.

Norm

tonycpe

I like your ride Norm.

don71

I am using this cam. My choice was based on the low-buck build I did at the time, this was 1990.

I wanted to keep the engine close to "stock". This included low compression,power brakes so no high stall and highway gears (2:56) and 100% street. It has served me well with no regrets. I was worried at the time, that it is easy to over-cam a street car. I did'nt want bad fuel mileage, it smells, rattles, idles rough and the wife won't drive it syndrome.

Well, things have changed since then and so are my future plans. I am looking closely at the JM 22-25 for ME. YOUR plans may be different.

Just ask your self, where or what rpm range is your car going to be in, most of the time? And build for that. Have fun.

88 coupe

Thanks.

Looked like this,



when I bought it.

Street driven, 12 to 1, 468, with this



cam. 11.30s @ 118.

Not my first choice, for a sleeper/stealth application.

Norm