I was wondering if rebuilding the stock LG 4 in my 87 Formula for supercharger was cost effective and reliable compared to a normally aspirated 383 stroker enginge which a lot of people seem to use. Does the 305 ci give up too much displacement to make a solid 400 rear wheel horsepower? I have been looking for comparisons here and through out my extensive magazine collection. Any thoughts?

 

the only way i would keep the 305 is if i had a boat and needed a good anchor. if you want 400 hp then build a 350/383 or look into an LSX swap. just my .02

 

Its not really about the displacment difference. Any built engine with the right boost will make power. Its about the heads, 305 heads suck compared to 350s. Look at the LSX engines the smalls ones ( 5.3) can make some good power because they have great heads and " I hate to say it but also the FORD 4.6L also great flowing heads with more valves. And it would be more cost effective and most likely cheap to build a 350. My last (2CENTS) go LSX, 5.3 are cheap way cheaper than a LS1 and you can get over 400hp @ crank with just a camhaft swap and a tune.

 

If I was looking for 400hp reliably at the wheels (about 460-500hp at the flywheel with an auto) I would probably be looking at a 383. The reason for this is simple. With the 305 you're going to have to not be afraid to lean on it in order to get that sort of power, even with ported heads/intake and a fairly stout cam.

As for me, I want about 400 at the wheels with a 305 but I'm willing to trade off reliability. 305s are cheap enough, I have 2 spares here that are under $100 for both. The first plan is:

ported heads/TPI intake, 204/214 cam (smallish, but I'm skiddish about tuning a bigger cam yet and if it can get a 3.8L into the 10s it should be able to feed my 305 okay) and I'm going to do twin GN turbos I have sitting here after I get it running well. I Think it'll make 400 at the wheels but I also have no illusions about it doing it for 100,000 miles reliably and I'm willing to put some methanol injection or race gas into the mix to make it happen. For the price I Think I can have considerable amounts of fun however, especially compared to building a 383.

 

i'mgoing for a similar build this spring i want to rebuild the stock 305 an single turbo it . i like the idea of getting as much out of the original motor as i can . i figure with a hx35 i'll get around 400-500 hp which will be a fun street car . good luck with your build

 

your not going to get 400 rwhp with a stock 305 and a turbo..

my 305 is a stock bottom end, i have heads/cam/exhaust, methanol injection, 14psi of boost, i put down 380hp/420 ft lbs to the wheels.

and even if you make 400 to the wheels you cant lay it down and if you lay it down prepare to break the trans and rear

 

I agree 100% my first car ran like a bat outta hell but had major traction issues 305 89 formula with a paxton running 8 psi

 

what kinda track times are you running ?
traction issuses would be wecolmed , right now 380 at the wheels sounds fun i think

 

my best was a 12.6 at 110mph with a 1.79 60'

i havent been to the track much, i launched kind of easy

 

my last car was a 05 srt4 with a 50 trim running 23 lbs. of boost . i ru 12.71 at 113 mph with a 1.98 60 footer . i want to beat that with this car by next fall . i'm going for a mild street setup stroker kit with forged internals for this 305 an elederbrock heads a lt1 cam either twin 50 trims or a t 76 turbo .