this is more of an after-thought, i suppose, but with installing a larger cam with more lift and having the heads done, should i go to a larger bore throttle body? stock is on there right now, guess it's a 44 and running good with it, but was contemplating a 48... thoughts? opinions? still has stock plenum and intake, btw, on my 350 TPI.

 

A quick vacuum test in the plenum during a WOT pass will give you the answer. If you're getting an inch or more vacuum at WOT then you could benefit from enlarging your greatest restriction ahead of the plenum (which could possibly be the throttle body).

 

On a TPI engine the stock throttle body is 48mm. You could upgrade to a 52mm or 58mm....i suggest the 58mm b/c its the same price and the more mods you do, then more the bigger throttle body will be useful. However, the biggest bottle neck on the TPI system is the base. If you haven't changed that.....that would be a great first start along with the throttle body.

 

I would spend the 300-400$ elsewhere first.

U will see barely if any gains on a stocker.

Spend the $$$$ on headers/catback or base and runner first.

Lot better results for your $$$$

later
Jeremy

 

i have headers and catback already and plan to stay pretty much stock for the most part for now so i guess i'm pretty well set with what i have. i was thinking stock was 44, not 48, but now that YenkoST mentioned it, that does ring a bell... thanks for the replies...

 

305sbc thanks for that tid bit of info. i had never heard that before. makes me wanna go test mine now to see if my stock tb is holding me back.

 

Put the money elsewehre. You'd see more gains with something like a good converter and gears. Ignition upgrade, underdrive pulleys, lca's and relocation brackets, panhard rod, the list goes on. TB isn't the bottleneck of the engine, the stocker will flow enough air to support those heads.