A friend of mine has an '89 Firebird 305 TBI and he's asking me what he should do to modify it. He'd like to keep it as a daily driver, and running on premium. Wondering what a decent head/cam/intake combination would be?

I suggested he switch to carburated, but he'd like to stay with the throttle body for fuel economy. Was thinking switching him to the 670 cfm holley TB, decent vortech heads and vortech intake?

All help/suggestions/advice would be appreciated.

Thanks guys.

 

Vortecs/Vortec Intake/670CFM TB or 454 TB/Full exhaust. I've read about good results over on TGO about that setup.

-Rippin

 

I have heard that injector spacers and 1.6 rockers make a good difference. Plus get headers and cat-back.

Is it 5 speed or auto?

I have an auto and added a corvette servo, Transgo shift kit and 4.3L stall converter and open element--reduced et by 0.3
(the transmission died on me so i had to get it rebuilt)

 

She's a manual. Wondering what cam would be decent? Nothing to give it TOO much of a harsh idle, he'd like it to remain smooth at idle and all...but something to replace the peanut cam?

kinda trying to be economic so don't really want to do the heads, even though that'd be a big gain. For now might just do the 670 TB, full exhaust, open element, and cam. Maybe a short throw? Anyone know a solid short throw for the manual? Would a B&M ripper do the trick?

 

The Ripper should be perfect.

 

I can't object because I've never used one, but I sure can tell you the Pro 5.0 is SWEET! Precise shifts, real short throw, all around great shifter.

As for the cam, just an LT1 cam would wake that LO3 up. The reason I say LT1 cam is because they can be had for like $40 and I really haven't looked into/read about cams for LO3's. Good luck Brant!

-Rippin

 

I'd go;(if not a 350 make it one...)
K&N air filter
1' T/B spacer and injector spacer.
headers + high Flo cat + cat-back dual out.
chip + T-stat
moderate cam/double roller chain, like 206-212* .465"-.480", 112*LSA
Dual-Snorkel + air filter housing, cold air by deleting high beam lights and putting the snorkel hoses there.
Holley 670 T/B
Holley or Edlebrock intake
........plus the usual tuning and free mods....

 

Your cam choice sounds good. I'd do an open element instead of dual snorkle. They're hard to find and more expensive (Open Elements are like $20). I actually think I'm about to get one. The Performer RPM intake usually does well with TBI.

-Rippin

 

Well what I would if he is Hell bent on staying with LO-3
Get the 670cfm tb and get spacer's you'll have a 710cfm TB when your all Done thenn a K&N Xtreme box would be Ideal.
then I would get some 3.73's still get 15-17mpg easy.
well heck BRANT you should know this my 91 GTA Ramair 2 came with a 350TBI in it I know your all like 350TBI but yes that what it is,exsplain I can't i wish I knew why it got a 350TBI when i woudl think it should hvae a 350TPI but anywho Gm will do anything for buck......
But when i got it i had 3.42 gear's it had 175K on it it was tired but I swaped some 3.73's in it and got a 3" exhaust under it
and sadly my TBI V-8 was beating the stock L-98's and a few of the early LT-1's ,well on the street any way only run like 0-50mph
now if i satuyed on it with them around 70 - 75mph the L-98 would start walking me.........
but i could hold some of them LT-1's till 63- 67mph......
Drive skill ??? Godd Luck??? who know's but it happend a few time's that summer so it couldn't oif benn a fluke.
I did stay ahead of an LS=1 till 45 -50 MPH then they'd walk me like i wasn't movening so i am sure them race's was more or less all gear's .Now the B4C's wher 95% LB-9's but %5 of them had 350TBI's I'm Told my local dealer that my car was either Someone order the b4c package on the GTA witch he said would of been rare but possable, or who ever odered the car get it with the L-98 and when it came in had the dealer modify it to the 350TBI and 3.42's witch is what tom at don miller said was the most likly bet.....Tom said " if you wanted it a certain way you had the money and pitch a fit Gm would give you what you want"or his other idea was The dealer ordered it that way. but anywho th 350 blew up and i am in the process of puting a daul TBI 406 in it.

 

oh My sorry I got off subject.
yea in the case of you friend's LO-3 I'd say the same thing we told Derek, Brant 670cfm TB, 3.73's,bigger exhaust, possably cam head's ect.
then it should rock for a 305 yet stiil have sheap insurence and awsome gas milage like 17-15mpg if you drive it like me .


P.S Brant get your self some nice pant's with paded seat cause you may have beaten my old 87 L-98 GTA last summer , but this summer i got the feeling its going to be the
KNGHTRIDER 327 eating my exhaust smoke. well maybe not but I know that the 91GTA Ramair2's 406TBI will smoke yea.......providing i get traction...... but for and the rest of winter i'll to the big bad327 all hail KNIGHTRIDER LoL Lmfao

 

Do full rear suspension (lca's, relocation brackets, phr and a tq arm), posi, 3.73s, full exhaust with SLP headers, 3" cat, 3" catback, and spray it. Without spray you'll go low 15s, with spray you'll hit 13s. Easiest way and you wont need any computer tuning, which if you have a cam you'll need a lot of.

 

.480" lift is too much for the stock heads and valve springs. If you keep those, dont use a cam with more than .460" lift.

 

292*Dur.475Lift. would be ok .

292*Dur.525lift would be Perfered.

292*Dur.575Lift is what i got in my 406TBI

But i think it's going to be way to much a Lo-3.

But any one of them 3 Would kci some But with 3.73's behind it....

 

292*Dur.475Lift. would be ok .

292*Dur.525lift would be Perfered.

292*Dur.575Lift is what i got in my 406TBI

But i think it's going to be way to much a Lo-3.

But any one of them 3 Would kick some But with 3.73's behind it...