3400 MPFI?

[stonemason90]

Ok first off.... Im new to the site..... Names Stone... I drive a 1991 Pontiac Grand Prix SE Coupe with a 3.1 mpfi.

Okay... enough with the formalities....

First off... Sorry its so long.... Didnt mean to make it this long when I started typing....

The cam twisted on the grand prix so I decided to go full bore performance with it.... I talked with Ben over at WOT-TECH and he tells me I should use a 3400 short block and put my 3.1 MPFI heads and externals on it. Anyone know how I would go about doing this? Is it a simple take off here and put on there job? Or is there a bit of modification involved? Which is fine with me..... And what exactly would the benifits of putting the 3.1 heads on the 3400 be besides the fact I could use all the original sensors and equipment. Would it increase compression because it has a smaller combustion chamber? Oh and the goal is to hit around 225-250 hp at the crank....Yeah I know... a high goal for a lone backyard builder like I am, but hey.... if your gonna do something might as well aim high....

Oh... I know how critical some 60*v6 guys are of the MPFI motors.... Been on enough grand am, beretta, and grand prix forums..... They too have their benifits... So please no bashing... helpful responses only....

[bszopi]

First off, welcome!

Secondly, your power goal is going to be hard with a Gen2 top-end. They don't breathe anywhere close to a Gen3 top end (3x00). If I was going to do with, I would just swap in a 3400 and run it off of your stock computer. There are enough 3x00 swap chips available out there that it would be fairly easy to find (Ben might even offer one - can't remember). At least then you'd have a much better base to build off of and it would be easier to achieve your goals.

[stonemason90]

Hey... I said I was aiming high lmao.... Go big or Go home.... lol
Thing is... I want it to look original.
I was thinking the same thing however I was thinking i could polish the intake ports as well as the heads. Then put a bigger throttle body on it. I know they sell adapters for the bigger throttle bodys. The benifit I was looking at with it though is the 3.1 head would be raising the compression slightly which will benifit me seeing as its gonna be naturally aspirated with an auto trans. Ben said I could see around 180 hp without doing anything else other than just the conversion. So that alone puts me pretty close to where I'm aiming for. I'll probably make a set of headers as well as redo the rest of the exhaust. Which will help it breath a little better. 20-25 hp gain over basic conversion? If so I'll hit the mark right there. Practically I'd like to see 200 hp at the crank anything over is a bonus.

edit.... But using a full motor thats rated at 220 hp stock is cheating lmao jk...

[bszopi]

A 3400 isn't rated at 220hp stock, though... Its only rated at 175-180hp (depending on platform). I think Ben might have mis-spoke when he said you'd be at 180hp with just the conversion. There is no way a Gen2 top-end, even with slightly higher compression, it going to yield the same HP as a stock 3400.

[stonemason90]

My old 2000 Grand Am GT1 was rated at 225 hp. It had a 3400 motor

[mickaz]

check this tread it will help you decide

http://60degreev6.com/forum/showthread.php/47085-3400-heads?highlight=mickaz

[stonemason90]

check this tread it will help you decide

http://60degreev6.com/forum/showthre...ghlight=mickaz

I'm going the other way around. lol 3.1 mpfi heads and fuel system on a 3400 sfi short block.

edit.... Oh and the specs I got from the old user manual. Which I dont have anymore.

[bszopi]

My old 2000 Grand Am GT1 was rated at 225 hp. It had a 3400 motor

If that's what you were told when you bought it, you got lied to...

http://consumerguideauto.howstuffworks.com/1999-to-2005-pontiac-grand-am-8.htm

[bszopi]

And another, which matches the above : http://www.internetautoguide.com/200...826/index.html

[stonemason90]

If that's what you were told when you bought it, you got lied to...

http://consumerguideauto.howstuffwor...grand-am-8.htm

read edit please.... lol

[stonemason90]

I'm going the other way around. lol 3.1 mpfi heads and fuel system on a 3400 sfi short block.

edit.... Oh and the specs I got from the old user manual. Which I dont have anymore.

The owners manual lied I guess...

edit... wait no... Now that I think about it yeah your right.... it was 175/205...... my bad....

[bszopi]

I don't know what to tell you other than that's incorrect. No 3400 has ever been rated from the factory >185hp (minivans). Even the 3500 only makes 200hp.

[SappySE107]

No, I told you a 3400 would be about 180 hp. What you are talking about doing is maybe 150hp at the crank. The cam and bore are upgraded, thats it. Port all you want, the gen 2 manifolds suck too bad for it to ever reach its potential. This is why 3.1 owners swap to the 3400 top end, performance. I told you to get a 3400 block instead of buying a rebuild kit for your 3.1 (new crank, rods, pistons, etc). I didn't tell you to keep the top end for a performance build. I said it would make it easier to install and would cost less.

The stock 3400 is 175-185 hp.

[stonemason90]

No, I told you a 3400 would be about 180 hp. What you are talking about doing is maybe 150hp at the crank. The cam and bore are upgraded, thats it. Port all you want, the gen 2 manifolds suck too bad for it to ever reach its potential. This is why 3.1 owners swap to the 3400 top end, performance. I told you to get a 3400 block instead of buying a rebuild kit for your 3.1 (new crank, rods, pistons, etc). I didn't tell you to keep the top end for a performance build. I said it would make it easier to install and would cost less.

The stock 3400 is 175-185 hp.

I thought you were saying with my top end it would make around 180 lol either way the bottom end in the 3.1 is done.... twisted and bent cam= carnage...... So a 3400 is as simple as a chip swap for the original obd1 computer? Or would I have to get a new computer as well? Then what can be done from that to make it around what Im going for which is around 200+ bhp.

[SappySE107]

Chip is for a stock 3400. If you had a laptop, ALDL cable, and a chip burner, you could use the OBD1 tuning service to dial in any setup you want.

http://wot-tech.com/shop/all/obd1-tuning-service/prod_271.html

For 225-250 crank, You can modify the 3400 however you want then. port work, cam, larger TB, etc. If you push it closer to 250, then larger injectors would be a good idea.