jbcmyk

i'v got a 92 rs 305 tbi w/ 180k miles +, i would like to drop in a new GM 350 from there catalog / chevy dealer crate motor. the motor i spoke to the parts guys about was a 350 w/ 330 hp. it should bot to my ttranny. i would need a new distrib and vortec manifold. has anyone done this?

i may also need a new chip/computer for the new set up.

looking for some direction if its possible and or problems to look out for.

gm part number 12496968 or 12486041.

it would go in a daily driver w/ modified suspension and braking.

thanks

john

chefdan1

i did this exact same swap only carb. the motor is very sweet. i was very surprised and pleased with it. you might want to upgrade the stock 700r4. it can handle it but you might as well do it all right.

bhe way i outran a 99 z28 with my car last night.
just want to tease you on what the motor is capable of

BronYrAur

iTrader: (1)

There are a few guys over on the TBI board that have done the 350 ho swap like that. JPrevost being the main swapper that comes to mind. If you want to keep TBI with that combo you'll need the vortec manifold with a tbi adapter or the vortec tbi manifold and you'll definitely need bigger injectors (probably at least the 65pph cop car injectors). With that kind of power you'll probably want a throttle body with 2" bores rather than the stock 1 11/16" bores or at least do the ultimate tbi mods on the stock one. For the chip you'll want to get a caprice cop car prom for the 8746 but you'll probably still want to just use that as a starting point and modify it yourself. You may want to get a VAFPR as well to go along with that. I'm sure that'd get it running pretty decent.

There's actually a thread near the top of the TBI board right now pertaining to this swap fyi.

jbcmyk

sounds like keeping the tbi may be some work, how about going to carb?

thanks
john

BronYrAur

iTrader: (1)

I'm actually doing somewhat of a similar swap right now too. I'm swapping in an L98 but keeping my TBI on there. It actually doesn't look like it will be that much work and keeping the fuel injection would be much easier in my eyes than having to tune in a carb, but if you have experience with carbs then by all means go carb it'd probably be much easier then. For me though TBI shouldn't be too bad, you need the new intake either way you go, then you can usually find some 65pph injectors pretty cheap and just mount them on your stock tbi after doing the ultimate mods to it, so that's not too hard. Then you can buy the cop car chip off ebay or www.tbichips.com for like 30 bucks and the vacuum adjustable fpr is like 40 bucks from GM partsdirect. I think either way you go you'll have some work tuning it in, you just have to decide which way you're more comfortable with.

jbcmyk

i am totally new to this stuff, whats vacuum fpr ?

BronYrAur

iTrader: (1)

The VAFPR is a Vacuum Adjustable Fuel Pressure Regulator. The fuel pressure regulator is a small device on your TBI unit I'm sure you can find pics of it in the technical articles on this site. Basically the vacuum regulator has a hose that can plug into a vacuum port on your intake manifold. It detects levels of vacuum and sets your fuel pressure accordingly. This is good for engines putting out high horsepower because it will keep lower fuel pressure at idle and then at WOT it will boost up the fuel pressure to handle the horsepower and high rpm.

Deemax

iTrader: (1)

I did the 305 - 350 TBI swap last year. The advice you've got so far on here is good. You need the bigger injectors from the 350 (I just swapped entire TBI units...externally they're identical), the knock sensor from the 350, and a custom chip. Other than that, its pretty straight forward. You can see my mods in my sig...I gotta tell ya, I couldn't be happier with my engine. It's smooth as silk, but with 300HP, it's got enough guts to have some fun. Not to knock the Goodwrench, but for what you'll spend on that, plus the distributor and manifold, you could probably do just as well to find a 4 bolt block from a medium duty truck and have it built up just the way you want it.