Daniel Mitchell

Did they make a TPI 305 in the Z28 in '91? If so, how much hp did it have and what kind of numbers do they run? I'm sure it's less than stellar but just curious. Does anyone have a good running 305 TPI combo? What are the best mods for these, just a good 350 upgrade? Thanks.

unvc92camarors

yes they did and go to thirdgen.org
then click on tech database for numbers and everything else
one of hte best upgrades is a 350 of course but simple intake, exhaust, gears, and maybe some 1.6 rr would be beneficial and net a few tenths in the quarter
and if you have an auto, a higherstall t/c would be great too
and don't forge the free mods like t/b bypass, and cut out for the air filters, etc.
do a search is my best advice

aklim

383 Upgrade. 8.5 compression and a blower.

JAY'S 91Z

I have one that runs pretty good - see sig

Lt1 and Ls1

I had a 91 z convertible with a 305 and it rocked!! It was really fast!

stanghunter211

I think 1.6 rockers would be a little much for stock heads. Good for an LT1 and a pretty popular mod, but a I don't think 083 heads would be a good candidate for this. And there is a bit work involved just to get that little extra lift, which the heads might not even be able to handle. Can anyone concur?

Will

unvc92camarors

doh
i knew i've been hanging around lt1 boards too much
sorry about that, he's right
the heads are sorta not too good on the 3rd gens
and i'm not really sure if there is any work to get the extra lift, never really thought of it
thanks for pointing that out to me though

aklim

You'd have to take the heads out and have them machined to accept better springs and take the lift.

stanghunter211

Yeah thats what I was thinking. I didn't wanna come off as correcting you bro, just tryin to save someone from maybe doing something they coulda done without?!? I know cuz its something I heard alota my LT1 buddies talking about, and I wanted to try it, but all the info points to no...

Will

Daniel Mitchell

Is that with a 305 and no head work? Sounds nice.

aklim

Sounds risky to me. Stock heads are not meant to take that kind of lift. It could but you might break the spring. That would drop the valve into the piston and that would suck.

stanghunter211

Yeah, thats why I wouldn't mod my stock block like that... Some guys are just lucky I guess, get a good strong block from the factory

Will

kandied91z

i suppose if you had a manual they aren't bad from the start and slight modding is better then nothing but there is a huge difference between a 305 and 350 car.

JAY'S 91Z

With the exception of what's in my sig, this 305 is stock. The 1.6's and springs went right in and in my case they help my motor breathe a little better. Also I still have my stock valve covers. The key to all this is (no offense to anyone on this board) that I'm not 18 anymore and I tend to only get into it when it's absolutely necessary (ya know mustangs at red lights, the ocassional trip to the track, etc) still no guarantees tho, but when it goes maybe I can get some real hp haha

Kevin91Z

You CAN put 1.6 rockers on a stock cam & heads 305. However, you should replace the valve springs at the same time, as they will be worn out. There are several ones out there that are stock replacements, no need for machine work.