2.41 to 3.73 gears story, and TBI can make power.

[oldmansmonte]

Thanks for the info. I might PM you with a few questions if that's cool.

Any time!

 

[ssiron]

Any time!

Did anyone have driveshaft problems going to the 3.73? When I did mine I had all kinds of problems. Finally had a 4" aluminum made and finally it runs smooth. Tried several things to fix, tried a rebalance, had a new 3" steel made none of this helped. Vibration started around 60 mph and was really bad.

 

[olds307 and 403]

Makes sense on the bored TBI, the 454 TB added a lot of power when it wanted to work right. No doubt the tune needed reworked, the 94 swirl port sucked on my Olds powered 4x4. It ran OK in closed loop with the idle turned up slightly and the timing advanced 20 degrees. In open loop it couldn't keep up with my 8.5 to 1 Olds 350 with a 204/214 cam.

 

[oldmansmonte]

Makes sense on the bored TBI, the 454 TB added a lot of power when it wanted to work right. No doubt the tune needed reworked, the 94 swirl port sucked on my Olds powered 4x4. It ran OK in closed loop with the idle turned up slightly and the timing advanced 20 degrees. In open loop it couldn't keep up with my 8.5 to 1 Olds 350 with a 204/214 cam.

I've been told the 50mm TBI for the 454 won't run well on a small block. To hard to dial in. I actually have a Holley 50mm TBI unit I bought years ago and never ended up using. Never got around to selling it either.

 

[olds307 and 403]

The main issues I had was throttle sticking issues and crappy sensors. Every sensor was toast on the TB I picked up and even the replacements were more money than the later sensors, required adapters and were flakey. It would easily spin the tires with the 454 TB and the gov lock rear, not the case with the cleaned up 350 TB. So yes, a matched to your year TB over bored is the best way.

 

[UNGN]

I

I use the GM performance TBI intake. It's a pretty nice unit. Aluminum and such.

https://www.summitracing.com/parts/nal-12496821

Boy the prices have gone up on those since I bought mine. I'd look for one used if you could get it. Edlebrock makes one as well. Edlebrock makes great stuff, but with these beware before buying. Edlebrock lists theirs as being .250 taller than stock and won't fit on B body Caprices. So I don't know what that means for the Monte but it could be trouble. Also with the GM there may be 2 part #'s depending on what year heads you have.

It looks like a $60 swap meet Performer manifold with a $40 TBI adapter plate would duplicate that manifold for $360 less. Would be easier to go into and clean up the ports, too.