i was looking at maybe a 389 or 400 but not sure. my brother (91blkrs) said i can bore out a 350 and change the heads to make a 389 and i think thats what i want to go with but just checking with u guys. if you can bore out a 350 to make a 389 how big of a bore and maybe some good heads ideas? ive heard the 389 has alot of power potential what are you guys take on this?

 

I don't understand how the heads affect the cubic inch displacement. Regardless, there are some fairly common size small blocks, but a 389 isn't one of them. Maybe he's thinking of a Poncho. Did he mean a 383?

Chevy now sells a 383. IIRC, it is a standard bore 350 (4.0) with a 3.8" crank. Needless to say, there are a variety of crankshafts available.

Do the least amount of overbore, given the wear in the block and then figure out what size crank you need.

 

well i think it is a poncho engine. ive seen the rebuild kits for it in the Pontiac Performance mag and was going to order it when i get the engine. i dont know my brother said the heads give the engine like more power to reach higher performance for bigger engines but w/e hes an idiot. but ive seen some one else on this site who has a 389 if i can find him again.

edit: i think old GTOs came with 389s but idk

 

Poncho engine won't work. Tell your brother to put down the thinking cap. a 400 SBC will work great through

 

See the only problem with that would be the difference in engines. You said that you were taking a 2.8 out, so I'm going to assume we are talkign about the third gen bird. The problem with putting a true pontiac engine in the car is the size of the engine. These things arent small. You will find that the mounts are completely and totally different from the mounts for the sbc that would have came in the car. Also you have to think about exhuast. You stand no chance of finding headers or a ypipe made for a pontiac engine to put in a third gen. But, it can be done. Has been done. Its just a matter of whether or not you have the time, patience, or money.

 

There are kits & headers available for teh Poncho swap inthe third gen. As far as engine size comparo goes, You've never seen how much bigger a bbc is compared to the Poncho mills have you? It's really a big difference.

 

But the BBC uses the same mounts and transmission as the factory SBC. That's significant.

I don't know enough about Pontiac engines to say whether you can bore a 350 to 389. Wouldn't surprise me, but different heads would be a must - that much I know. But, if you're going to all the trouble to put a Pontiac engine in, why not a 455? Same weight, same hassle, more power.

389's were the original "muscle car" engine. But, they don't make as much power as a 400 or 455. For the same weight. I know a lot of guy running 455's, but don't know of any running a 350 or 389 except in restorations.

 

I've seen a whole lot of ponchos. Probably more than you have. But, I've never seen one in my life in a third gen. The whole compare a BBC to a poncho is useless. What I said was compare a poncho to a sbc. Have you ever seen a sbc? Sounds arrogant doesnt it, just like what you said.

 

Keep in mind your Firebird isn't really a true Pontiac with a Pontiac engine. It's really just a Camaro with a different body package. So swapping in a Chevy engine is the easiest and most economical approach. And you have to keep in mind that even though the 389 Pontiac was a performance standard in it's day... well, those days are long gone. There are much better options now.

The most common 'stroker' engine is a 383. It's a 350 engine with a larger stroke. They are great performers and you can find bolt in kits everywhere. Check out www.speedomotive.com for the type of stroker kits you can build into a basic 350 engine.

 

i used to own a 1961 pontiac catalina with a 389 in it and it was a powerfull engine but i think youd be making a mistake tryin to fab one into your third gen when there are so many other possibilities you could use such as the 383 stroker or just a 350 they bolt right in and there are headers and all the accessories you would need available in a salvage yard or from a parts store where your gonna play heck findin all the right pulleys and brackets to make it all work right in your car