I'm putting a budget 360 together for my 84 shorty truck. Street and stip use no hauling or towing. just a bracket rig and tire burner. Getting tired of the current slant6!

The truck has 3:55's and a sure grip 833 od tranny. The 360 short block is a mid 70's low comp version that will only be treated to a re-ring and bearing.

I'm using a set of ported heads of the same vintage only they have 202 valves in them. Again left over from another project that was upgraded to eddy heads.... I'm going with an edelbrock performer as the truck a/c and it is the only intake I have fits with that.


Here is my real question. I have 3 camshafts left from various other projects all are used but in fine shape with lifters in order.

One is comp cams 268 and another is comp 272.

The wild card is an old purple shaft I once took out of a 340. It has to one of those old 108 centerline cam as we had an issiue with detonation and swappimg it out for a wider centerline cam solved the problem.

Wouldn't this work well in my low comp 360 by building up the cyl pressure? Or would one of the more modern comp cams be a better choice.

This is basically a junk motor with me using up some old parts that are laying around.

Comp 268 if thats all you have.

I dont know the LSA on the 268 or the 272 but if they
are wider than the purple I would use the purple and
install it at 102 to 104 centerline just for the purpose
you stated... upping the cyl pressure

The only problem is the MP hyd cams with 108 lsa are over 290 degrees(I know they don't list them as such),so you can advance them all you want and not produce cylinder pressure with under 8 to 1 comp. The old standard comp 268high energy is ground on a 110lsa and most install it around 106lca,much closer to usable than the larger duration MP cams,IMO.

With no comp,not enough gear,somewhat heavy truck I would not worry about top end and kill it dead where it needs to work.

the 268H is 218/218 .050 dur, .454" lift

the 272? do you mean the magnum 270H? is 224/224, .470 lift

I have an XE262 in my stock long block 360, pulls real good from about 1800-2000 up to 5500. if you've got a loose (2500-2600 stall converter, and don't care about idle quality, I'd probably go 270H. if your converter is more in the 2200-2300 stall range or lower, the 268H

use comp 901 springs with either.

I'm going to check what I have I think both were xe cams?
The mp is an old 284/484 purple shaft/108 I'm fairly sure of that one!

Truck is 4 spd..no worries on stall speed.

what first gear ratio is it? unless it's a 3.09 first gear tranny, I'd stick with one of the two comps, probably the smaller one.

Speaking from experiance DO NOT USE THE 284 cam the truck will be a dog period no matter which way you install it.It plain kill cylinder pressure I'm using a very similar setup using a LD340 and 750 Holley dbl pumper. The Cam is a comp 268 high energy. I have tested seven cams and the Comp-268 has given me the best times in a 4350 racing weight car. With the 284 cam the car ran a 15.8 with 3.55s. The car ran 15.0 to 15.2 same gears Comp268.
The key to getting your truck going is in the timing and carb by tuning and gearing I got this car to go 14.30. The comp cam is out of steam at 5700 but will rev to over 6000. So key here is do not over gear!.Also run the total as high as you can and not detonate try 45 total. By the way this car is another example like you are doing using parts from my other car and making it run Have fun !

But I'll add a few bits,hope it helps someone. Even at 3100lbs with 3.91 gears and 3000 stall converter the 268he gave near identical times to the 284mp cam low 12's 110-112 mph. The 268he cam was shifted at 5200rpm,the mp284 6000rpm. The MP really liked more converter and gear to wake up. I'd bet the peak torque with the 268he would be 3500-3800 rpm and peak hp 5000rpm for a close ballpark.I found the 268he also favored small carbs over carbs that work with hotter combo's.

I built a simliar engine for my valiant. Stock 360 pistons and heads. I used a 480/480 lift 292/292 duration 230@.050 109 centerline. It runs well with 4:30 gears and a 2600 stall.

We had a .030 over 360 9to1 comp with a erson 214 @ .050 with mid.400s lift in a pick up with a 2500 vert and 3.55s I think it was 108 on 104, air gap and 660 holley , ran good 2500 to 5500 in 4500 # 4x4

Got an OD; gears can be changed.

Go big cam and don't look back!



Bet if you had 5.13's that purple shaft would be the clear winner...

Then again, I'm NOT known for having anything resembling common sense regarding comfort/drivability.

-Bill

Wow going have to let this all sink in!

So it sems that I go with the 268. I'm assuming that I should install it at 106?

So how did it work? I'm going through my Lil Reds 360 and still undecided on cam and pistons. Thinking KB232 and comp cams 268 or 270. Going to install a 2000 stall, what's the better cam for a heavy truck?

My rebuild is getting put off till winter.I managed to pick up a v8 wiring harness as well as a few other pieces to finish the swap just need to free some time to get her underway. . My shop has been busy with paying customers lately !