Hello everyone, great site and great boards, with that said here is my problem. I just bought a 92 RS with a TBI 305 and auto trans, after changing the oil for the first time and replacing it with 10w30 I am having a knocking in the bottom end of the motor, sounds like a bearing. Now I am at the point of either rebuilding the motor or swapping it out. What should I do, and if a motor swap is a better choice what motor is an easy drop in? Should I stay with the TBI or not? Should I stay with a 305 or go with a 350? Thanks for all your help.

 

dude get rid of the 305. most 305 and 350 parts cost the same. you will get more power out of the 350 and spend pretty close to the same amount of money. you will be happier in the long run. lots of guys on here with a 305 or had a 305 (such as myself) will tell you the same thing.

 

I would rather go with a 350, what all will I need to swap for a 350, and should I go with carb'd, tbi, tpi? will I need to get a comp chip, or should I look for a motor with ecm?

 

Go with the 350, you'll be happier. Also I'd ditch the TBI and go carb, but that's just my opinion, I'm not a big fan of fuel injection. Do a search for the vortec heads, performer rpm, XE274 combo... 420ish hp and pulling down mid to low 12's on motor.

 

If I swap to carb, what other mods need to be made?

 

You'll need an AFPR and have to route the fuel line differently. Other than that I think that's about it, or at least that's all I can think of....

 

Whats an AFPR?

 

Adjustable Fuel Pressure Regulator, you need it to step down the high pressure from the fuel pump. Carbs like 6-10 psi fuel pressure, but the TBI injectors need way more than that, so you have to step it down if you go with a carb.

 

Thanks kfoley, I just finished reading the tbi->carb swap and I am planning on going that route. What would be a good donor motor? What should I look for and avoid? I have the stock 700r4 transmission, will this handle a 350 with roughly 350 horsies? And also will the rear end withstand the power?

 

If I were doing the swap, I would build up a motor, but if you don't have the time/skills/tools/space whatever there are some good crate motors out there. You might look at the ZZ4 from GMPP, 355 hp and 400 some odd tq. Makes for a pretty stout motor. The tranny will be able to hold it fine as long as you're not too rough on it (and it's not a V6 tranny, they're a bit weaker), I would reccomend a bit higher stall though, it makes a big difference. As for the rear, it will hold up fine, just don't plan on putting slicks or drag radials on it and it will hold up. If you do the unltimate 10 bolt mods on it you should be fine with drag radials, but slicks are definitely not reccomended for any 10 bolt, they just aren't strong enough.

 

you will need a distributor also.

 

I would love to go for a crate motor, but not in my budget, I'm looking for something that runs good nothing super hopped up or anything, I wanna do that down the road, so I'm looking for a descent 350 with a carb. What motors should I look for? Out of a car or truck? Thanks again for all the help.

 

I'd look for something out of a vette or camaro/firebird. Not the Gen 3 motors of course, they'll cost you an arm and a leg. An L98 from a late 80's early 90's vette (aluminum heads) or camaro (iron heads) would be what to look for.