I have a 92 roadmaster in my backyard with a 350 TBI, it's sleeping and going to the scrap yard soon. Is it worth taking it out to swap it in a TPI thirdgen? What's the different with a 350 TBI from a third gen? The engine is pretty good shape so I figured it was better than buy one from the scrap...

waiting for your imputs guys
thanks

 

The 350 block isn't any different than the iron L98 Fcar 350s. It's a Buick so there is a chance it had more regular maintenance (oil changes) than otherwise so the block might be in decent shape, and worth rebuilding.

The main difference in the TBI vs TPI engines is the heads, and of course the intended use. TBI engines tended to be in heavier cars and light/medium trucks. TPI always went into F or Y cars. TPI engines got higher power ratings, but they also had bigger cams and slightly better exhausts.

The heads on the TBI 350 are swirl port (193 casting number), while the Fcar 350 heads are not. In stock unported form, the Fcar 350 heads (083 casting number) flow better on the intake side but more poorly on the exhaust as compare to the 350 TBI. A mild cleanup on the TBI heads along with radiusing/bullnose on the swirl ramp edge and on the valve guide bosses helps a lot and would be worth doing in a cheap 350 build together with a cam swap.

Lo-tec used a junkyard Cad TBI 350 engine in a 3rdgen. He did nothing to the heads. He added a carb, headers, and a mild cam and got into the mid 13s in the quarter mile. So you could do as well with the Buick engine. If you keep the EFI (TBI or TPI), you will need ECM tuning to match.

So using the Buick 350 in an Fcar would be worthwhile if the engine is in good shape, and you don't expect huge power from it (i.e. 250 hp or so). If you seek big power, then you would really need better heads (Vortec, or aftermarket equivalent) and spend more money. HTH.

 

There was no 350TBI in 3rd gens, the only 3rd gens with a 350 had a TPI motor. This is a better engine, however if you're thinking about using this 350TBI to replace a 3rd gens 305TBI, (or maybe a 305 TPI) then of course you're laughing. Drop in a bigger cam (the phrase "peanut" cam has been uttered more than once), and tinker with the TBI setup and you're golden.
It'll have provisions for a roller cam, and it's not that old, so less wear. This puts it above most JY 350 blocks as far as desirability.