could one of you guys tell me what you would suggest for a low end rebuild in a TBI 305. i want to completely swap everything. i was thinking a .30 bore would be nice, and i was gonna stick a 100 shot of nitrous in too. how much would this cost excluding the machine work.

 

You can pick up some descent rebuild kits for 300-400 bucks. Those usually just come with hyperuetectic pistons. If your wanting to load that motor up with nitrous then spend the extra money on some forged pistons. Just to be safe from grenading it. But if you tune it right for nitrous then hyper would be ok.

 

what cam should i use. also what should i do about my throttle body, keep it or do a conversion?

 

with a total motor rebuild you're looking at around $600 for machine work. a good shop will bore/hone the block (WITH A STRESS PLATE) and dress it (freeze plugs, cam bearing) and also shoot the seats/valves in the heads as part of the rebuilt procedure - this is all assuming that you hand them the motor and make them tear it down - if you did the tear-down it would be cheaper. as far as the bottom end, here's what i suggest:

1. Pistons - if you're running nitrous go with forged pistons - simple. they're relatively cheap in a rebuild kit from somewhere like summit or jegs and are definitely worth the money - make sure your ring gaps are set correctly and that the machine shop fits them snug (1-2 thousandths MAX) and they'll last forever. Also, if you have the tools and time, balance the pistons/pin combinations to each other so they all weigh the same - this can be accomplished with a die-grinder, scale, and rod-sling (it holds one end while you weigh the other)

2. Rods - real easy - use ARP bolts and balance the rods. Notice how Chevy's have big blobs of extra metal on the top/bottom of each rod? Grind them off until each rod's big/little end matches all the others.

3. Crank - if necessary, have it turned and then sent out to be balanced. You'll need to send the piston/rod/pin weights for each journal in addition to the balancer, flexplate to the machine shop doing this work. Its DEFINITELY worth it. Look to spend around $150 to have the crank balanced.

Thats what i'd do with my bottom end...just shy of buying nice forged rods and a forged crank...but thats when you've got money to burn - which i know i dont.

Ty

PS - if you have any questions, feel free 2 email me bsrboy@yahoo.com