305 CCC to 350 TBI in 86 GP

[CoachFoust]

I've done some searching and haven't quite found what I'm looking for...and I haven't done a lot of research elsewhere yet. So this is just me thinking out loud...

My 86 Grand Prix has the CCC 305. It now has blown head gaskets. I could tear it town and replace them, or I could just replace the entire motor with a TBI Goodwrench 350 with 67k miles on it. I don't know if it has the ECM and harness with it or not. I know I'll need those things. I also think that I'd need a fuel tank/sender out of a 4.3L TBI Monte Carlo.

Has anyone done this? Am I just going to be better off replacing the head gaskets in my 305? Opinions? Experience?

Thanks in advance!
Coach.

 

[olds307 and 403]

The stock TBI cam sucks, it is tiny. It was actually over rated at 210 hp. You need to stay 210 duration or less or 112 lsa or wider for it to play nice with the stock computer. Plus the factory swirl port heads are awful as well. That said it is still stronger than your stock 305.

 

[84slow]

I'm doing a tpi swap right now and to be honest some days I just want to yank out the fuel injection stuff and just run a carb. A lot cheaper

 

[kustomkyle]

Never done the swap, but having both a CCC car (1986 307 Olds G-body) and a TBI car (1993 D-body), the TBI is a bit more simplified in terms of how much "stuff" is attached to the engine, but slightly more expensive to service (cheap, but not as cheap as HEI).

It sounds like you have/have access to a truck 350 TBI, which would have a flat tappet valvetrain. That may or may not present problems as you've got many of the same cam lobe wear caveats you would have with an older engine.

Supposedly that was what bumped the truck engine up over 200 horsepower, apparently GM felt it was needed and more proven/rugged for truck applications. The 9C1 Caprices had a similar horsepower rating, and they also had a non-roller valvetrain, but supposedly an L98 Corvette style cam (?). When it's happy, and especially years ago, the 180 horsepower (300 ft/lb) roller cam 350 TBI in my car (roller cammed engines came in the full size B/D bodies, and F-bodies) feels like it's got a bit more than what it's rated at.

There were two intake manifolds, one specifically for the B/D body with a larger distributor hole. This was supposed to be for servicing the distributor in car, as the engines for that bodystyle were set back and under the firewall a bit. The Edelbrock intake available is the small distributor hole type, intended for the F-body (roller cam) engine or the truck/van (flat tappet). There shouldn't be any clearance issues in a G-body, so I don't see why the Edelbrock wouldn't work if you make the swap and feel inclined to add it.

EDIT: Due to the different intakes, there are two different distributors. Spectra/Richporter GM04 is the truck/van/F-body small hole type (would fit the Edelbrock intake), and GM32 is the full-size car, B/D Body distributor. As you would expect, the "GM32" is a little harder to find depending on where you look, for obvious reasons. Had to replace mine in the D-body because the base of the original corroded (common issue with this style). You have tiny screws holding the cap on, and the receiving threads fine pitched and made into the aluminum base. Be prepared to ream the holes out when the threads disappear gradually, and invest in tiny (5/32?) nuts for the backside.

If I had to guess, a lot of the 4.3L Monte Carlo stuff would be the missing link parts to make everything work. I have seen a few people doing this swap before here, so hopefully someone chimes in with more in depth information for you.

 

[87National]

I've done some searching and haven't quite found what I'm looking for...and I haven't done a lot of research elsewhere yet. So this is just me thinking out loud...

My 86 Grand Prix has the CCC 305. It now has blown head gaskets. I could tear it town and replace them, or I could just replace the entire motor with a TBI Goodwrench 350 with 67k miles on it. I don't know if it has the ECM and harness with it or not. I know I'll need those things. I also think that I'd need a fuel tank/sender out of a 4.3L TBI Monte Carlo.

Has anyone done this? Am I just going to be better off replacing the head gaskets in my 305? Opinions? Experience?

Thanks in advance!
Coach.

If you get the ecm and an uncut wiring harness, it should be a fairly straightforward swap. You will need to connect your TV cable - assuming you still have the 200r4 trans. If the TBI engine you are using had a 700r4 behind it..... the TV bracket should be the same as the 200r4.

 

[olds307 and 403]

The 350 truck TBI had a 165/175 .382/.402 cam, horrendous for a 350. The l98 cam was a much better either 206/212 .415/.430 on a 117.5 lsa or 202/207 .413/.428 on a 114.5 lsa. The car 350 was probably under rated, the truck 350 was overated. The 350 tbi in the trucks were very gutless. The wiring colour is the same, just the plug is different for your CCC distributor. You just need to ground the extra black wire. The 94-95 TBI computer is supposed to be the best, go to the wrecker and get a Harness, computer and all the sensors off a donor truck . I ran a 204/214 cam with a stock 94 computer. Ran a bit shitty in open loop but good in closed loop, of course it was an Olds 350. The l98 cam would work well with the stock computer and no doubt bump up power. Pretty sure most, if not all TBI blocks except the roller cam spiders.

 

[kustomkyle]

Trucks and all the cars except 9C1 Caprices used the same injectors. Standard part# TJ7. Roller cam/flat tappet cam.

The 1989-1993 Caprice 9C1 used a higher flow injector, TJ25, which coincided with the L98 type cam. If I'm not mistaken the 9C1's had their own ECM, but maybe it wouldn't matter.

People have used 454 injectors too, but that obviously would be for something heavily modified (as modified as a TBI engine can get). It's just a matter of matching everything up.

 

[oldmansmonte]

Ok I run TBI on a Chevy Performance 350 and it runs great.

Disclaimer: I am not an engine builder so others will have to correct me if specific parts won't work.

However it sounds like you can build a version of my engine on the cheap. Gm Part # 19210007.

Since you're going to have a long block already I wold recommend the cam mine came with (P/N 24502476), runs great with TBI despite some speculating it won't. If you can splurge get the 64cc Vortec heads. Cast Iron(heavy) but great flowing. Dollar for dollar the best you're going to to do on this motor (P/N 12558060). As far as intake Gm performance and Edelbrock made them. Easy enough to search that I don't need to post them.

As far as an ECU I got one from a 1993 fullsize 5.7 silverado. The only "problem" it encountered was the EGR code would come up and it would retard the timing quite a bit. You can easily have that programmed out. As far as injectors I used the 65lb ones for a TBI cop car. I'm sure the 55lb ones would work fine as well. The ECU's from those era have a 25% margin to adjust fuel so 65's are probably being used under capacity and 55's would to be closer to capacity. I did eventually have the car dyno'd to maximize performance, but even prior to that it ran good.