Hey guys, in an attempt to gain alittle more ponies out of my gutless 160HP (stock) 350cid in my '86 Chevy K5 Blazer, I am seriously considering a cam swap to help in the fight. I am a long way from building my 'dream' 383 for it, so I have to make due for now.

Here's my question. Is this a good idea on a motor with 100k already on the clock? The motor runs strong and smooth, great oil pressure, oil changed every 3k miles, etc. The cam would be a mild Summit hyd flat tappet grind (clone of the Edelbrock 'Performer' cam). Of course matching lifters and new Z28/LT4 valve springs/retainers will be installed too.

Plus, while the motor is out of the truck, the motor will be cleaned up and repainted. Also the following would be replaced and/or installed: Performer (EGR) intake, double roller timing chain, Melling oil pump w/ new shaft, aluminum water pump, Carter fuel pump, full length SMOG legal headers, etc. Hopefully I'll get another 100k miles out of it before a total teardown and rebuild is needed.

Since the truck was new it has never been able to break traction on the dry street. I always thought it was because of the factory posi-traction. But even after 4.11 gears replaced the stock 3.08's, still nothing. Breaking traction isn't a priority, but at least it tells me that I have room for improvement. If I could get 50HP gain out of all the mods, I'd be pretty happy.

How much do you think I'll gain with all the improvements?

Thanks guys.

I had an 87 Chevy truck and it had over 100K miles when I began to mod it. If the short block is sound (do a leak down test), you should be good to go. I think the cam will help, but those heads are the real bottle neck on that 350. I put a set of edlebrock performer heads on along with headers and dual exhaust. This made a huge difference. Later on I added the edelbrock performer cam and then the multipoint fuel injection system. The truck ran low 14's with 342 gears on street tires. The heads made the biggest difference and I'd strongly suggest you upgrade when doing the cam swap.

I'd start with a leakdown test. If the numbers are good, a cam, intake 'n' header swap could be a good deal.

You can do better than the Summit cam, though. They tend to be generic grinds, with little overlap. Maybe better than a stocker, but not optimum.

EDIT: Looks like we posted about the same time. Yes, the '86-95 swirl-port heads are crap. Total junk for performance. GM got a conservative 30 horsepower by dumping the swirl-ports and going Vortec on the 350HO crate engine...and you're planning to replace the intake anyway!

Thanks for the replies guys. A head swap is out of the question for the moment. Vortec heads are also out of the question because of California SMOG.

A leak down test has already been done and everything is good to go.

My truck is a early '86, 2-piece rear main and DOES NOT have the crappy swirl port heads (Thank God). I am sure the heads on it aren't the greatest either, but still better than those swirl ports.

As far as the Summit cam, its all I can afford at the moment. Anything has got to be better than the stock peanut cam w/a whole .320" of lift and 180 dur@0.050". Plus overlap isn't SMOG friendly either.

Like I said, if I can gain 50 HP/TQ from the mods I will be happy.

Thanks again guys.

I have that cam (sold under the Melling brand)in my driver. It works pretty good and will be an improvement over the stock cam. It really, really likes 1.6 rockers. I don't know that you'll get 50 hp but you will get a very noticable improvement. While the heads are an issue, with a small cam like this (204/214@.050) they may not be much of one. I'm not sure it will pass smog, though. My Melling cam is speced at 278/288 adv (204/214@.050) so it has some overlap (59º) but I don't know if this is really accurate. This old design cam has very shallow ramps and it may take quite a few more degrees before flow actually starts. Mine idles quite smooth but you can tell it's not stock (barely) but I have 1.6 rockers. The specs of my driver are linked in my sig, if you care to take a look.

Just to clarify, I didn't think I was going to gain 50 hp with just the cam swap alone. I did hope that I would get 50 hp after the cam swap, Performer intake, and headers.

Still think I am aiming too high?

Thanks Pat.

Do you plan on improving the exhaust? Keep it simple and build it for torque, and you won't go wrong.

Maybe not. Headers are probably good for 20, maybe 30hp. So you just might get that. There is the potential of more than that. Take a look at my driver specs. According to Engine Analizer 3, it makes 354 Lb/Ft of torque at 3500 rpm and 289hp at 4500.
Here is the read out:

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> RPM 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
Brake_Tq 138 217 277 328 350 354 350 337 301 250
Brake_HP 26.3 62.1 105 156 200 236 267 289 286 262
</pre>[/QUOTE]

Your engine is different but not a lot. I have manifolds and not headers. Don't put a lot of trust in these numbers. Computer sims are not truely accurate. I have better heads, SR Torquers, but they are very much like old stock Chevy heads. I suspect the 1.6 rockers are helping a lot. I tow my bracket car with this engine. It works pretty well for that.

If you want a little more power! Go with the Crane 266/266 Energizer..

It's just about the next step up from the Performer cam being talked about..

Or the split-pattern of it, the Powermax H-266-2 at 266/272.

Either cam should be a real dandy in a P/U, at least to me..

But I don't know about the smog thing so maybe just a Crane Compucam 2040 at 270/276 but on 114 centers to help the smog inspection.

pdq67