are all 86+ 350s roller cams? I have a buddy that needs to swap a 350 in his 89 siverado. he already has a 350 but if he goes to an older block will he be able to get the tbi to run right? or does he need a roller engine or a block upgrade to a roller cam?

He wants to keep the tbi but only needs a long block 350 and we found a great deal on one but it is a 78 block. I was wondering if he can use this or if the flat tappet cam would mess up the duration and whatnot that the tbi likes?

Please help soon!!! If this works it helps him save money and I will get the roller 350 to rebuild and a rebuilt turbo 350 trans out of the deal really cheap.

THANKS!!

 

I don't believe 80's trucks cam with roller cams, even though the it is a roller block. The block can be drilled and tapped for the roller lifter "spider" hold-down though.

 

I also believe that all near stock cams grinds should work fine with the TBI FI setup.

 

thanks ME Leigh.

anyone else? Also is there any problem with any accesories or water pump, etc.?

 

Get the casting # off the block and go to http://www.mortec.com/castnum.htm

There's a slew of numbers that will tell you more about that block.

FYI, the SBC didn't get roller cams until ~'87 and the truck didn't get them until ~'95. Some of the '87 and up blocks got the provisions to hold the factory roller cam, but I can 99.9% guarantee that the '78 doesn't have them.

There's really no need to worry since his truck didn't have a roller cam anyway. FWIW, the only things that you may have problems with are where the dipstick is located, and the fact that the '78 block has a two piece rear main seal, so you'll need a different flexplate for the transmission. The 1 piece rear main came on '86 and newer blocks. They made the bolt pattern in the rear smaller in diameter, so the flexplate from the truck won't bolt up.

One more thing is the heads. The stock TBI intake manifold won't bolt up to the older heads without having the inner four holes (the ones closest to the TB) elongated to match the angle of the holes in the heads. AFAIK, all TBI intakes had the newer angle.

Other than those things, the only other problems I can think of would be accessory holes in the heads. They may have been in different locations on the older heads, but it's hard to say.

 

Oh yea...... as far as the TBI liking the cam...... that depends on the cam.

As long as the cam is able to hold at least 15in/Hg of vacuum at idle, the MAP (Manifold Absolute Pressure) sensor will be cool with that and tell the ECM everything is OK. If it drops more than that, you'll have to find a cam with more LSA (Lobe Seperation Angle) or less duration @ .050", or both. All the ECM cares about is a steady and relatively high vacuum.

If the cam in the block now is too aggressive, then it will cost you a whopping $100 to get the right one. Just look at the ones at www.summitracing.com that are sold as Summit cams.

 

I would have to say that AJ_92RS is pretty much on the money. I can say that from experience. I had a 92 Chevy 4WD silverado with a 350 in it and I did an engine swap in it, but the motor I replaced the factory motor with was bought from Jasper, and it was a slighlty hotter cam than factory. I had to fight with the timing a bit, but I finally got it right. Everything else on the truck was the same before and after the swap, but the cam was basically a "R.V." cam and the engine I got was bored .030" over and it had slightly higher compression. When I set the timing to factory specs, the exhaust manifolds glowed red. I got it home and played with it a bit, and drove it for years. The Jasper motor was truely awesome, and did very well with that setup. I was told that if I had put in a chip that it would have been even better, but never got around to it before I sold it. The ecm seemed to do fairly well and was pretty forgiving for having the extra cam and with it being bored 30 over.