283 questions

I was just wondering what a good estimate of HP my motor has so I can better plan for the future of my truck. This is what i have: 1972 chevy c10 lwb fs. under the hood is a 283 from a 64 nova 202 hump heads from a 67 or 68 350 edelbrock performer intake holly double pump 600cfm carb mallorry HEI extreme energy cam 283/289 and heddman long tubes thats about it. no machine work all original internals besides cam and lifters.


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if those heads have the 202 valves your looking at trouble, i had a pair of 375 double humps with the 202 valves and that smacked my pistons. need something smaller.

I doubt you will want to hear my personal opinion, but w/o going into the gory details of why this is mismatched, I would say that if you swapped out the short block for a 350 or 383 short block, you will be a LOT happier w/the performance.

If you want to keep the 3" stroke, you will need heads that will keep the CR up as well as the keep the port velocity high to ever hope to use the potential of the cam. The way things are now, the engine might have peak power above 6K RPM, with a CR below 9.5:1.

In your case the 2.02/1.60 valves are more of a hindrance than a help. They will be shrouded w/that stock bore. The heads have reasonably-sized ports, though. You may well need a smaller combustion chamber to get the CR up or use domed pistons, but they have there own problems. A decked set of 305 castings would be a low-buck approach to solving the problems associated w/the "fulie" heads.

And you will need steep gears/loose converter w/a 2004R or wide ratio 4-speed.

Changing just the cam to something less radical (something like the Comp 262, as an example) would be a move in the right direction, if you were to do nothing else, IMHO.

Good luck.

I did not build this motor but i have the documentation from when it was put together and when things were added so i pretty much know what i have but this motor has about 3500 miles on it and have not had any trouble yet. I'm sure they checked clearances. are you sure you were configured right??

well cobalt327 that cam i listed is not in the motor (everything else is) i listed this cam because the comp tech line said this is the one i need. The cam right now is a 286 ho6 Way too big!! A lot of guys want those heads. should i sell them and if so what should i put on it??

Personally, I like the double hump heads, too. I like the way they run, and have zero problems w/them- except when on a small displacement engine.

Unless you're "married" to that particular short block, I think that switching it out for a 350 (I know, everyone has one- but there's a reason for that ), you will really enjoy the combination, as long as a cam is chosen to compliment the CR.

A 350 will be a beast, compared to the 283.

I'm kinda at a loss as to why that cam would be Comp's recommendation, unless I'm missing something (a distinct possibility, BTW). What's the specs on that cam, if you have them?

The cam that is in it Intake 102 exhaust 110 duration 230 advance duration 286
the one they recommend I'm not sure but the pn is 249-cl12-238-2

Turns out that cam is: Xtreme Energy XE262H Hydraulic Flat Tappet Camshaft Only
Lift: .462''/.469''
Duration: 262°/270°
RPM Range: 1300-5600

That coincides w/what I had recommended earlier- "(something like the Comp 262, as an example)", I thought the advertised duration numbers were 283/289, which would put the duration @ 0.050" higher than what the 262 cam is.

That cam would be about as good as it gets w/your current combo.

performance and reliability wise what are your thoughts. still too mismatched or will this be reasonable. I also intend on installing a stage 2 700r4 and 3.55 gearset. ???????????

I think that cam will be as good of a match for your combo as you are likely to get, and that gear/tranny combo will help matters, at least at take-off. You will still be pulling a 2.6-something rear gear when locked up in OD, though. But that's less of a problem than it sounds like, because (thankfully) the tranny shifts out of OD as soon as you add throttle to it at cruise.