86 grand prix 305 help

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I am getting this grand prix from my uncle, for nothing! and i know that the engine will only run about 150to165hp and the car weighs about 4000+lbs so im not really expecting any crazy speed from it, but the question I have is this.
about how much horsepower do you think I would free up by taking out the catalytic converters and or adding headers and exhaust etc...

and also some good tips to make the car look nicer, just little stuff...

anyway, thanks

posted by  nighthawk

that car doesnt weigh even close to 4000 pounds maybe 2700 or somewhere close to that.

posted by  adamc44

advertised curb weight on a '84 w/ a v6 is 3259... and i'm assuming that's dry...

posted by  dodger65

i knew its wanst close to 4000 because i just junked a 88 chevy caprice with no m/t and it was 2300 lbs.

posted by  adamc44

but aside the weight issue, how much power can we awakened from removal of the catalytic converters and or other ristrictions in the intake and exhaust?


and 2700 lbs or 3200lbs is prety low for this car i gotta say it:2cents:

posted by  nighthawk

we took my friend's 84 w/ a 305 crate motor in it, (this was a while back) put a mild cam in it w/ a edelbrock performer intake and a 600 holley. exhaust was cheapass blackjack headers w/ turbo mufflers and dumps in front of the rear axle. 3.73 gears w/ auburn posi (blew out many sets of spiders before the auburn...) and a th350 w/ b & m shift kit. was very quick for what it was. the only unmodified cars it had problems w/ were 5.0 stick cars.... he gave an 87-88 iroc a 3 length head start and was in front of him by the time he hit 2nd.... fun car and reasonably cheap...

posted by  dodger65

Yeah thats some pretty good stuff there, but I dont think I want to do a whole lot of internal work with the engine, just an exhaust system to make it sound better and breathe easier, and maybe later a supercharger or something more extreme, (later on of course ) but does anyone know about how much hp and torque would be added with just the exhaust stuff? , and how much a supercharger would add to the engine, with the other things done,

I dont mind ball park figures, unless you know for sure, but yeah

thanks anyway

posted by  nighthawk

hey bump, This thread was going alright for a little while

Ive got the car now and im still wondering if anyone knows about how much horsepower will be released by removing the catalytic convertors and other power restrictors, and does anyone know a definite weight of the car?

thanks people

posted by  nighthawk

the weight is on the title. as for the HP thing, don't bother with the 305 engine. save your money and buy a BOP 350 rocket or even an old pontaic 455. even those engines stock will do some damage on teh street and at the track. but i guess if you are hell bent on keeping that tired POS 305, headers would wake it up. i suggest taking a look at this site http://www.geocities.com/gforcejohn/products.htm. they sell crossmembers made for putting headers on your car. they eliminate the need to go under the stock one so you have more ground clearance. im sure you could have someone make one, but those are already made for you with all hardware to install them. they also make crossmembers for different tranny set-up as well. after you get that figured out, get some gears for the rear-end. 3.73 gears would probably wake that car up a little, less top end but faster acceleration. hope i helped :thumbs:

ERROR CORRECTED

posted by  glagon1979

there is no bop 305... it is a chevy motor. if he gets a 350 rocket or 455, he's going to have to do a whole lot of changing to make it work... motor mounts, exhaust, custom headers, different trans (unless he's lucky enough to have one of those dual-pattern trannies)

posted by  dodger65

i corrected it. i knew that, just having a brian fart. i always liked the idea of keeping engines with the correct manufacturer. that car deserves a 455 with 3" exhaust and flowmasters, and who cares if its not a multi-fit case, buy an adapter.

posted by  glagon1979

well, heres how its supposed to go,

me and my dad are going to remove and rebuild the engine, start off fresh
then re-do the interior (torn seats and the usual stuff)
then things like a paintjob and new tires/exhaust/brake work/whatever doesnt fit anywhere else.


so i have just a few questions

1.is the 305 really THAT bad of an engine?
2.rocket 350? is that just any chevy 350?

and one question for the appearance people(just for kicks)

does anyone know a paintjob/color that brings out the body lines of a car really nicely?

posted by  nighthawk

OK, STOP!!!!! rebuilding a 305 can cost the same as a nice used 350. the 350 rocket was an oldsmobile engine and i don't know why i mentioned it, so disregard.

as far as the paint job, look at the car in my avatar. those colors folow the body lines with a pinstripe between them.

posted by  glagon1979

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