I am trying to find out if a 78 block is okay to replace an 89 block. both are 350s. it is in a silverado pickup and I dont know if the 89 350 in the truck is a roller engine or not. if it is, will the older non-roller engine be okay to put under the tbi?

I dont want the tbi to not function correctly because of the cam not being a roller. we are keeping the centerbolt heads. so we are just replacing the longblock.

Please help!!

 

The '89 block, if the original engine, is technically a roller cam block, but did not come from the factory with a roller cam. It has provisions for the "spider" roller-lifter retainer, but GM put regular hydraulic lifter cams in the trucks until the Vortec engines came out.
The '78 block is a direct replacement for the '89, but I would take the cam/lifters out of the '89 and put them in the '78 engine. The cam for the '89 is for tbi fuel injection, while the cam in the '78 will be very different and won't run right at all.
If/when you do swap cam/lifters, be sure to install the lifters on the exact same lobe of the cam as you removed.
A better option would be to buy either a stock spec replacement cam or aftermarket cam along with new lifters.
SC

 

i can kinda help on this too. you can use a non-hydraulic roller cam block without much problems. i did a 400 sbc swap this summer with a tbi setup. 97% done. worked fine (well, when she was running ). the type of cam (hydraulic/roller/flat) wont have an effect on the engine, just the specs of the cam.

 

Remember flywheels are different. The 78 is the 2 piece main seal and the 89 is a one piece and the flywheels are different.

 

That's right BRHARRIS. I forgot about that. SC

 

You will also need the oil pan and dipstick for the 78. The stock 78 truck cam will work just fine unless it is worn out(i assume this is a used engine) which would give you a good excuse to upgrade to something better. A cam with 250-260 adv dur/ 204º-206º dur@.050 and a 112º LSA works well in a basic stock 350 TBI truck engine for good low/mid range torque. Of course you will need new lifters and i would suggest a new timing set such as a cloyes C3023X.

Good luck!