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Dec. 10, 2011 9:48 p.m. IWELDIT New Reader

Does anyone hear have any experience building hi HP out of these, I know they are cheap and there are thousands of them out there. I also know they share parts with the v8 . Is there any limits I should know about,or major problems that will stop me from getting the HP I'm looking for. I am trying to get to somewhere between the 350 to 450hp mark.

I know every one says just build a v8, but I'm not normal that way. I like a challenge

I have no problem using some form of boost.

Oh yea,I need this to be done on a very small budget.
Dec. 10, 2011 9:58 p.m. donalson SuperDork

sorry no real info beyond the CPI pulls out 200hp stock and the turbo version in the sy/ty is 285... and as with most turbo engine can push out a lot more
Dec. 10, 2011 10:00 p.m. blizazer Reader

Www.fullthrottlev6.com is a good resource for those.
Dec. 10, 2011 10:02 p.m. fasted58 SuperDork

go V8
Dec. 10, 2011 10:17 p.m. BoostedBrandon HalfDork

A 4.3 is 3/4s a 350, so all the same tricks work. Flat too pistons, bigger cam, exhaust. Edelbrock makes an intake,and aluminum heads I think, but they are not cheap.

For same money, you'd get more power from a v8, but I understand the desire to be different. This is GRM, after all.

I wish you luck, and look forward to whatever you come up with.
Dec. 11, 2011 12:52 a.m. novaderrik Dork

a 350 bolts in with only different motor mounts.. all the accessories from the 4.3 bolt to the 350.. why do you want to build the 4.3 again? to be different?
Dec. 11, 2011 1:14 a.m. pres589 Dork

About a decade ago Hot Rod Magazine did a build on these things using stock heads with a lot of time on the flow bench, I think ~320 hp wasn't that hard to reach. The heads are trash from the factory but any decent aftermarket replacement is stupid money.
Dec. 11, 2011 3:16 a.m. junkbuggie Reader

there was a guy that use to build the crap out of them for compact demo derby (no v8s was the only restriction on motors) he would just go to swap meets and drag tracks and find 350s with 7 good rods and pistons take the 6 best then standard head work. I dont think he ever got 400hp or even 350hp for that matter.
Dec. 11, 2011 3:30 a.m. novaderrik Dork

take the same amount of money and effort that it would take to build a 300hp 4.3 and you'd have a 400+ hp 350 that is better in every way..
Dec. 11, 2011 12:53 p.m. patgizz SuperDork

i'm in the same boat with my 92 sonoma. at 18xk miles, i want to freshen things up and make it faster, but i am not sure i want to do a v8.

i have a couple late model vortec engines to donate good heads, etc... but i also have a 350 TBI that will pretty much bolt right in and run with a 350 computer chip and injectors with no wiring changes.

the big reason for me to stay v6 besides 1-2 more mpg is to keep weight down, mostly adding the weight of 2 more cylinders worth of block, crank, heads, intake, cam out in front of the front axle centerline and moving the water pump and all accessories that extra 5" forward for even more poor weight distribution.
Dec. 11, 2011 6:35 p.m. novaderrik Dork

i put a TBI 350 out of a 92 Caprice into an 88 S10 4X4.. my total cost for special parts for the install was about $50 for a reverse rotation flex fan because there wasn't enough room for the stock clutch fan or an electric fan.. i used a set of 67 Chevelle small block engine mounts bolted to some home made adapter plates to bolt it to the stock 4.3 frame mounts and welded the sump from the 4.3 oil pan to the Caprice pan and used a 4.3 oil pump and pickup.. the tricky part was modifying the exhaust crossover pipe to work with the 84 Camaro 305 exhaust manifolds and clear everything.

i used the stock 4.3 TBI wiring on the 350 TBI and snsors and just plugged the Caprice ecm into the stock harness.. i think i had to run a wire for the IAT sensor, but otherwise it hooked up like stock.

it took me about 3 weeks of screwing around for a few hours every night in a 30 degree shop in the middle of winter to get it running, but once it was running it was an absolute beast. i was never able to get a title for the truck (long story- the kid that i got it from never got the title from the guy he got it from, who never transferred it from the guy he got it from- i paid $100 for it with no motor intending to part it out..) so i never drove it on the street. i scrapped the truck, but i've still got all the conversion parts.. i think a torquey 350 would get better mileage than the 17-20mpg than most 4.3's get in those things..
Dec. 11, 2011 8:55 p.m. IWELDIT New Reader

Ok hears my plan,the reason for the six is to keep the weight down on the front end of the car. As I do not have room in the budget for aluminum block V8. The guy up the street has a compleat van with the 4.3 just sitting there waiting to go the the scrap yard. Should be able to get it for next to nothing.

I was thinking of taking the motor apart and cutting and rewelding the rods, so i can lower the compression, then doing the home brew blanceing job on the pistons and rods and crank. Putting it all back together with ported and polished heads and intake. The I would add a large amount of boost with a megasquirt. All of this would be put into a small but nimble car from the mid 70s of British heritage.

When said car is done I would love to sell it or trade it for my wife's dream car. A late 50 to mid 60 VW.
Dec. 11, 2011 9:13 p.m. patgizz SuperDork

why do all that internal motor work just to sell the car? slap it in with your boost and sell it off.
Dec. 11, 2011 11:39 p.m. novaderrik Dork

IWELDIT wrote:

Ok hears my plan,the reason for the six is to keep the weight down on the front end of the car. As I do not have room in the budget for aluminum block V8. The guy up the street has a compleat van with the 4.3 just sitting there waiting to go the the scrap yard. Should be able to get it for next to nothing.

I was thinking of taking the motor apart and cutting and rewelding the rods, so i can lower the compression, then doing the home brew blanceing job on the pistons and rods and crank. Putting it all back together with ported and polished heads and intake. The I would add a large amount of boost with a megasquirt. All of this would be put into a small but nimble car from the mid 70s of British heritage.

When said car is done I would love to sell it or trade it for my wife's dream car. A late 50 to mid 60 VW.

let us all know how well the rods hold together after you cut them apart and weld them back together.. hell, make sure you take a lot of pictures of every step of the process and post up a video of the initial startup..

i don't know what method you are going to use to make boost, but no matter which way you go it will wind up weighing at least as much as a mild naturally aspirated 350 that will make the same amount of power..
Dec. 11, 2011 11:52 p.m. pres589 Dork

This has to be a slow-motion troll attempt on the part of the OP.