any block differences between TBI and Vortec

[iluvmy72]

Hi I have a 1996 burb with a seized Vortec 454. I do have a engine block from a 94 burb. Are the blocks the same? I was told that they are and I don't even need to move the heads because there were no "vortec" heads on the 454....is this true? If so all I need to do is move over the mounts and intake parts. Any more insite on this? Or is it cut and dry. I need to know.

[panhead57]

Mind you I'm no vortec expert, but my understanding is that the only difference is cylinderhead volume and intake so it sounds pretty straight forward to me

[Blazer1970]

With small blocks, a TBI enigine has a flat tappet cam and a Vortec uses a hydraulic roller. The bosses might be in the TBI block for the roller lifter retainers, but the machining is not done.

[70rs/ss]

Yeah the Vortec BBC is a roller motor and the Vortec heads are about 1,000 times better than the tbi peanut port heads, but if you are going to junk the Vortec motor I'll buy it, or the heads??!! You can put the 94 right in place, and it should work OK, but performance may suffer a bit.

[BossHogg69]

I do know for sure, but the blocks should be the same. All the '91-up BBC's are the Mark V style (roller cam is the main difference, so are the water passages on the heads from what I understand) The 'Vortec' heads from the '97 will work on the '94, and I would use them if I were you. it will bump the compression up on that '94 at least 1 full point, and offers much better ports.

[68c10owner]

Originally Posted by Blazer1970

With small blocks, a TBI enigine has a flat tappet cam and a Vortec uses a hydraulic roller. The bosses might be in the TBI block for the roller lifter retainers, but the machining is not done.

Some of them are machined for a factory roller cam. I had one that was years ago.

Originally Posted by BossHogg69

I do know for sure, but the blocks should be the same. All the '91-up BBC's are the Mark V style (roller cam is the main difference, so are the water passages on the heads from what I understand) The 'Vortec' heads from the '97 will work on the '94, and I would use them if I were you. it will bump the compression up on that '94 at least 1 full point, and offers much better ports.

I heard 91 was a split year, could be Mark IV or Mark V. I had a 91 454 that was a Mark IV. I don`t remember what site I saw that it was a mixed year but maybe someone could clarify it for us.

[BossHogg69]

'91 may have been a split year, but that '94 will most likely be a Mark V. Guess you could just look at the back of the motor for the 1 pc rear main, if it's already out of the vehicle??