Okay,
I have an 87 305 TPI, I want to make a 383 to put in there, and keep the TPI on the 383. But my engine is 87 so I take it that its roller cam and 1-piece seal...so the 350 I have acess to is out of a bus (don't laugh its free) so will I need to put centerbolt heads on the 350, what about the roller cam, can I just use flat tappet instead. And will I able to keep my TPI. Any help is apreciated. Thanks

 

The bus engine is most likely a flat tappet block with a 2 piece rear main seal.

The only differences in some of the truck motors is the cam's rotation on the distributer (Some truck blocks spin the distrib counter-clockwise)

Changing the cam and distrib will fix this. Remember that aftermarket retrofit rollers are expensive.

 

Oh, buy the way the heads and tpi should go on no prob.

 

Before you put any other money in the bus 350, have a machine shop check it for cracks. Why did the engine come out of the bus? These extreme-duty engines usually come out only when they are junk.

On the other hand, the block probably has 4-bolt mains and a steel crankshaft. The pistons are probably very low compression. The heads aren't even worth considering.

If there are no cracks (the main web area is prone to crack on extreme-duty engines), you will probably have to bore the engine block.

If it checks out, and if it is a 4-bolt, steel crank engine, you will have a great foundation for a strong engine.
jms

 

Well it is my grandpas bus he always trades tractors and junk for more junk, and he said I could have it I would go get it, so if its junk no ones hurt and if its not, more power to me. I have another question, will it hurt to keep it flat tappet and not convert it over to roller? thanks

 

If it is a hydraulic roller engine and you want a mild street performance engine, keep the roller set-up. You can, if you wish, use a regular flat tappet cam in a roller block, with the correct pushrods.

If it is a flat tappet block, keep it that way, unless you want to spend a lot of money for a roller set-up. Chevy made WAAAAY more flat tappet engines than rollers. Plus there is a much better selection of aftermarket cams to choose from, both hydraulic and solid lifter versions.

As I said earlier, don't spend any money on that engine until you have it checked for cracks.
jms

 

jms is right. before you spend any cash on this engine have it checked for cracks. The heads are probably smog garbage but the shop should be able to tell you whether or not they're worth using or not. The good thing about this engine is that most shops start with high mileage truck and delivery van engines because the way they are run seasons the block and makes it a good foundation to start with.

 

jms is right. before you spend any cash on this engine have it checked for cracks. The heads are probably smog garbage but the shop should be able to tell you whether or not they're worth using or not. The good thing about this engine is that most shops start with high mileage truck and delivery van engines because the way they are run seasons the block and makes it a good foundation to start with. I'm using a 77 truck engine in my 89 and I'm running a flat tappet cam. I would rather have a roller cam but I haven't had a problem with my cam yet.

 

what is the difference of having a flat tappet or a roller one? more tq, or hp, better power band? i am pretty sure that flat tappet can rev higher, right?

 

The advantages of a roller is the valve can be opened much more quickly and much higher in lift for a given duration so more power and economy are pluses.

True a solid flat tappet can run higher rpms.

I was referring to a hyraulic roller above. The king of all cams is the solid roller.

 

Thanks guys for all of you help. I hope everything works out for me.

 

What exactly is your source for this information? I don't know everything, but I've never heard this. The only engines I've heard of running backwards are marine, and then only one of a pair of inboards. Oh, also some military SBC's that were in personnel carriers way back when.

What year is this bus? It probaby won't make any difference, but most truck engines came with flat tappet cams. If flat, your best bet would be a replacement flat tappet - retrofit rollers for a non-roller block are EXPENSIVE! I'll agree about the heads & pistons - absolutely junk for performance. If you get '87-later style heads, your intake and valve covers will fit. The bus engine may have a two-piece rear main seal, which will require a corresponding flexplate/flywheel.

The TPI is going to limit a 350. Same story on the exhaust. Porting the plenum, bigger TB, aftermarket runners, headers & high-flow exhaust would help. The cam should be picked to match the induction.

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. 0.030 over 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlock header mufflers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, LT MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1/95.5 @ 5800' Bandimere.

[This message has been edited by five7kid (edited May 29, 2001).]

 

I don't remember the year but a SBC out of an old bus won the Indy 500. It was the last year the stock blocks ran competitively.
Later,,, Matt