I'm planning on doing an engine swap in my '91 Firebird, hopefully within the next couple of weeks. The original 305 TBI is on it's last leg - I'll be replacing it with a carburated 350.

So far, I'm leaning towards buying a GM Performance Crate Engine - the 330HP / 350 Engine to be exact. My goal is 375-400 HP, so I'd be swapping cams for a Crane PowerMax 272-2 (216/228 @ 0.050, 0.454/0.480, 112 deg). Other pieces of the puzzle will be Edelbrock Performer RPM intake and Holley 750-cfm carb.

Before I start buying parts, I was hoping that someone could answer something for me. What's the difference between the bottom-ends of the 330HP and the standard GM Goodwrench 350 Engine? They both have 4-bolt main blocks and cast crankshafts. Are the rods/pistons on the 330HP of higher quality? Will Vortec heads not fit the standard 350? If not, it would actually be cheaper to buy the standard 350 and slap a set of Vortec heads on it. I must be missing something.

 

I'd be scared at a goodwrench 350 if there is a chance it was made in Mexico.

 

That's the cam I'm using in my 305. In a good-breathing 350, 375 HP should be easy. I think you will want to change the valve springs, though, because the L31 springs they use on that engine probably can't handle that lift (only 80# seated).

The Goodwrench engine has a two-piece rear main seal crank, but otherwise is a good foundation for a budget performance engine. The HO engine does have PM rods. Vortec heads will bolt to any SBC-style block, whether a 262 or 400, or anything inbetween.

For a slightly better shortblock, the ZZ4 has a forged crank, PM rods, and hypereutectic pistons. Bolt on the heads of your choice (even the Vortecs, if you're so inclined).

 

Well, in my opinion, if you can afford it then get the GMPP 350 H.O. , the LARGEST difference between the two engines you listed is the block itself. The GMPP 350 H.O. uses the same Roller Block that's in the ZZ4 crate motor! yes, it is the EXACT same block, look up the part number. you'll need an intake made for Vortec heads, but you already have a 1 piece rear main seal so you won't need to change the flexplate (assuming you have an automatic tranny) i'm not sure if you'd have a diff. flywheel for standards. the goodwrench 350 has a 2 piece rear main seal ... so along with changing the flexplate/flywheel, you will also need new bolts to attach them because they are a different length. if you re-use the bolts from a 1-piece seal on a 2-piece, they will hit the block before even getting them tightened all the way. i've been looking at both of these engines extensively because i will be replacing my 305 also, so if you have any questions, send me a pm or somethin'

 

Get the HO motor, just remember all the little things that add up and make sure you know how much money you're going to spend.

The HO motor seems better in every way(but price).

 

Do a search for posts by JamesC. He swapped in a 350/330. IIRC, he's happy with that engine.

With the parts you are going to be swapping/adding, wouldn't a short block be a better choice?

 

Did anyone else notice this is a 4-year-old post? And that the originator's info now says "408 SBC"??

 

One bad thing, about that motor is I think it has cast pistons, same with the one with vortec heads. GM Performance has the same motor,$ 2300 base, it may be a little better, tolerances. Jegs Performance has a GM Performance crate ZZ4, with a more radical cam than you were going to use, with 355hp & 405ft.lbs., . Aluminum Heads, simillar to vortec, and forged pistons, undercut and rolled forged crank, a better bottom end, a better motor, and do'nt have to mess with the cam, for $3800. Exhaust system could get you to your target h.p. . p.s.- Hope you got a good Tranny.

 

uhhhh...nope