301 to 350 small block swap

hey guys, first post on the forum so here it goes.... i'm thinking on buying a 80 firebird that was a v6 originally but had a 301 swap. now that i'm gonna buy it i want to swap in a 350. now i'm wondering how much work this involves. like should i do it or just rebuild and build up the 301. i'd love to have the 350 because of the aftermarket support and potential of the motor. but want to know how much time and money i'm going to have to put into it. i'm just wondering what has to be swapped, like motor mounts, transmission, driveshaft..etc. thanks alot  

Are we talking about a pontiac 350 or chevy 350.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

it would most likely be a chevy 350, they are easier to find round here, but have been looking around and it sounds like a pontiac 400 wouldn't be to hard of a route to go, but just started looking so it might be to early to tell lol  

ok i was just looking around and i found a pontiac 350, a chevy 350 and a pontiac 400, so i'm wondering which one would be the easiest to swap and will result in the best bang for my buck when building it. thanks everyone  

Sense your bird already has a Pontiac engine in it going back with a Pontiac engine will be the easiest swap.
The Chevy will be the cheapest but wont compare to the torque either Pontiac engine will put out.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

Ditto with the Pontiac engine. I swapped out the turbo 301 in my '81 Trans Am a while back and put in a Chevy 350. Yes, the parts and support are more available, but I never achieved the same torque. The motor mounts have to be moved for the Chevy engine, it will need a different transmission, A/C brackets are different, and oil will leak from the timing cover no matter what you do. After it's all done you still don't have the bottom end power of a Pontiac engine without putting in a lower ratio rear gear. Pontiacman8 suggested in another post that the 301 might be worth building up with some carefully selected modifications, you might consider that route. The 301 is a bit of a rare engine and could easily put out what the Chevy 350 would - plus, it's already in it!  

alright, looks like i'll be sticking with the pontiac engines, don't think i'll go with the 301 tho, my power goals are a bit higher then the 301 can offer. now to find out what transmission is in the thing, but have to get it to check that out, thanks alot for everything guys, i'll keep u's informed on the swap and how its going, along with some more questions proabably lol.  

Good luck! (a good old 400 is the only engine that ever lifted my front wheels off the ground - rice burners said "what just happened?" and limped home). A good transmission guy can fiddle with a 350 tranny valve body and provide extra smiles.
Screeeeeeeeeeeech! Chirp!   Chirp!   Chirp!  

What is your power goal.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

Im looking to get 350 400 hp and as much torque as possible along the way  

That would be easy with the Pontiac 400 and very possibly with the Pontiac 350 which one are you going with.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

i think i wanna go with the 400, from what i hear the thing can be a mean beast, which is exactly what i would like to have sitting under the hood of my bird, thinking of caming it, new intake and carb, duels, and possibly headers. this will be over time tho cuz thats alot of money to throw into the engine after a rebuild. i got alot of research ahead of me tho before i decide what i'm gonna do to the engine, gotta do some reading and see what would be best to get to my power goals or above.  

What is the casting numbers on the heads.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

You made the right choice going with a 400 Poncho- your car be worth more and be immediately welcomed by the Pontiac community (try parking a Pontiac w/ an SBC at a Pontiac show and you'll know what I mean). 350-400 hp from a 400 is straightforward, but it will cost a little more than a SBC.

The best block for your application is a 70-75 no.481998 400 block, which has the 5 mounting holes per side- this bolts in to your chassis and is stronger than the no. 500557 block, which has thinner main webs. Earlier 400 blocks will work too, but will require an motor mount adapter to bolt to your subframe.

You can either use small chamber 72cc D-port heads (no.12,13,16,48,62,670) w/ dished pistons, or the 98cc 4x or 6x-8 or the 94cc 6x-4 w/ a flattop. The smaller 72cc heads have 2.11/1.77 valves and screw-in studs, and the later model heads 2.11/1.66 valves and screw in studs. Whichever head you use, getting the heads ported will raise flow to the 230-250 cfm range- the short side radius work in addition to bowl work and some smoothing the chamber is key to achieving your power goals. Make sure to have this done by a builder who does Pontiacs and not Chevys, as the two are completely different.

Upgrade your rods and valves since the stock parts will fail in performance use- 5140 or 4340 forged Pontiac rods go for around $250-400/ set, well worth the extra money over a set of resized cast rods. 1-piece forged stainless valves are also much stronger than the stock 2-piece valves. Many Pontiac 400 builds either use the cheap cast pistons or the usual forged Sealed Power/ TRW flattop ($350)- I like the forged KB ($400), which is lghter than the SP/TRW unit and has floating pins. The rotating assembly should also be balanced to assure long life and healthy bearings.

Geno  

Hey guys, I'm going to take one last look over the car today cuz I never seen it in like 2 years but had one more question,  it's about trannys, don't know anything about em. And have an opertunity to pick up a th400 with the 400 and am wondering if this is a good tranny or should I just look for a better one?