Hey guys, I recently picked myself up a '85 Trans Am. This is my first real project car and I'd like to get 300-350hp out of it for now.

The car was originally a 305 TBI automatic, but now it's got a first gen 350 with a Quadrajet carb and a T5. It's got vortec heads, Edelbrock 2101 intake and roller lifters. It's straight-piped from the exhaust manifold back, no cat.

I haven't been able to find the engine's casting codes, but the previous owner said it was out of an '80s C10.

So what kind of power am I starting with? My first engine mod will be a full exhaust with headers, but I'm not sure what I should do after that.

Thanks!

 

Since it has Vortec heads and roller lifters, it's no longer "out of an '80s C10". That identification no longer applies, since "out of" a vehicle describes things like the heads, cam, & pistons it's equipped with.

Set up properly, with a decent cam, that combo should do 300 HP easy. Shouldn't be too hard to get it at least close to 350 for that matter.

What cam is in it? What pistons? (don't say "stock" unless you know FOR SURE they're the originals, which is bloody unlikely; instead, tell us the dish volume and MEASURED deck clearance)

 

I suppose I meant the block was originally from an 80's C10.

Can I ask why it would be unlikely for the cam and pistons to be the originals? My understanding was that adding vortec heads onto an old block was easy bolt on power with no other mods needed.

My butt dyno tells me it's already close to 300hp, but the current tires I have are junk, so it's hard to tell. The engine revs up to 6500 RPM no problem, if that tells you anything. It also idles pretty smooth at around 800 RPM.

I'll have to look up how to measure the dish volume and deck clearance since this is all very new to me. Thanks for the quick response!

 

Sure it's an easy bolt-on.

However, the odds of a 30-odd yr old motor getting transplanted into a different car, with different heads, and with a roller cam it didn't come with (NO 80s trucks did, with only rare unpredictable random exceptions), but all this WITHOUT it being "rebuilt", are pretty small. THIMK: would YOU do that to YOUR car? Well, most likely, nobody else would either. Doesn't mean it's impossible, or didn't happen, or couldn't happen, or anything of the kind; just, doesn't make sense in terms of the known real world and what goes on in it.

Of course it would be worthwhile to post the casting numbers of the heads, and make sure they're really Vortec; and tell us how you know it's a roller cam.

 

So far I'm just going off of what the previous owner was telling me, but he didn't seem to know exactly what the specifics were either. He only had the car for a year anyway.

I also haven't really had much time to work on the car yet because it's been too cold for it outside.

But anyway, I was looking at the engine last night and I noticed that my valve covers are not the centre bolt style, which means they can't be vortec heads unfortunately.

But then I noticed a large "880" cast into the side of the block. After some research, I think that makes it either a 350 out of a '95-'00 C10 or a ZZ4 crate engine block? They came with a roller cam, but I don't know why someone would take off the vortec heads?

Now I'm more confused than before!

 

Get the casting numbers off the heads.

Measure the deck clearance of the pistons. Estimate their dome volume, or post the part # on them, if they have one.

Verify that the cam is REALLY a roller.

Once a motor has been opened up, the only way to know what was put back inside it, is to open it up and look.

All else is idle speculation and a total waste of time and bandwidth.

They do stuff like that because they are humans. I've noticed since being assigned to this planet, that the creatures that consider themselves the "highest" life form on it, are illogical, irrational, and prone to consider short-term gratification over any kind of long-term value construction. In this case, they may well have done that, because they wanted to keep them, but had no use for that particular block.

The beauty of the small block Chevy is that EVERYTHING bolts right up to EVERYTHING ELSE. You can take a 1955 block and bolt 1999 heads right up to it. There are literally THOUSANDS of camshafts available that will slide right in any of them. You can take a block with a lowly 75 Impala 2-bbl stamping, and put 12½:1 dome pistons in it, and make a 600 HP racer out of it; or, take a block with a 71 "Z/28" "LT-1" stamping on it, and put in 12cc dish cast garbage pistons with the extra .020" of deck clearance and slap a pr of 624s on top, and replicate the 165 HP wonders of the mid 70s. (aka the "260 HP" "GM Performance" motor you can buy today) Looking at the block casting, or worse, the stamping, will tell you NOTHING about what the motor ACTUALLY IS. Gotta look at the parts and machine work. No other alternatives exist.

If you want to know what that motor is TODAY, take it apart and look at it. If you don't want to take it apart, it has no choice but to remain a mystery.

 

I suppose you're right! I've never really dug into an engine before, but I suppose it's the only way to figure out what I'm working with.

Thanks for your help and quick replies sofakingdom!