johnnyph

I just rebuilt my TPI 305 in my 89 Formula. I polished and ported the stock heads,installed Crane's powermax 2030 roller cam,roller rockers, Edelbrock shorty headers,160 Thermostat,Hypertech chip,Hurst Billet plus shifter,MSD 6A box,and ported the plenum. I already had modified the airbox,MAF,and installed an air foil. The fuel pressure has been set to 50 with the adjustable reg. Everything else (roller lifters,pushrods etc.)are brand new. The option or build sheet from Pontiac says the engine has 255HP@4400 295lb@3200 stock. What kind of increase should I expect??

i8myz28

iTrader: (1)

WELL, lets see you've seem to have done some homework on your parts...not a bad selection. you must have spent like $1500.00 in parts, but mathmatically speaking you probably gained 50 to 60 hp.. Alittle question for you though WHYdid you rebuild a 305 and not a 350 theres no substitution for displacement....we'll good luck , hope you don't get eaten by any stangs or 55 chevy's.....

ThirdGenFire

The 305 did not have those numbers thats the 350 are they not?
The 305 made 220hp or 230hp. It made decent horse power but not no 255hp I belive thats the Vette L98 motor that made those numbers.
Yeah those mods will help a lot. I am sure you'll see about 60hp. Good luck I know we need it seeing to a how we both have 305 TPI motors. Hey Preston Smith ran a 9 second 1/4 in his 85 Iroc-Z with the 305 and a turbo. So theres hope for us.

johnnyph

just to be sure i checked again, LB9 5.0 mk6 manual trans 3:42 axle 255@4400 295@3200 the L98 with Md8 auto 240@4400 340ftlb @2800 3:23 axle. This build sheet is listed for Firebird only. Everybody says the same as you but I have the sheet to prove it. Believe me I often use it. Thanx for the reply I appreciate it. P.S. any thoughts on fuel pressure?? 50 psi OK??

87350IROC

iTrader: (2)

Frst off, i would think 50 would be a little high but to really tell you need to get it on a dyno, or get into chip burning and diagnostics. Second the 305 did not have that much power. The 350 of the year was only 235hp or so. You may have a sheet saying otherwise but it is wrong. Can you post a picture of this document?
JP

johnnyph

I tried to post it but there is too many bytes. However give me an E-mail address and I will send it to you. By the way where did you get you specs from??

johnnyph

Never mind I found your address. Let me know that it went through

SweetS10v8

Just resize it, or change it to a jpeg

SweetS10v8

Here is what it looks like for 89.

1. 305 your talking about
2. 350 Single cat
3. 350 Dual cat

LAFireboyd

iTrader: (3)

Oh geez, another "why didn't you drop in a 350" guy. What's the matter? Not talented enough to build your 305? Just playing with ya, lol.

And there are plenty of 'stangs out there that can handle a 350. But at least, if we lose to one, we've got nothing to feel embarrassed about.

Sounds nice johnny. If you ever dyno it, let us know what you've got there. But I too have always thought those numbers were for the 350. But you're not the first to report having this info for the 305, so it's obviously published somewhere. I'd also like to see it posted.

87350IROC

iTrader: (2)

i was unable to open the pic. Anyway the info is from GM, Magazines, this website, and other websites and they all agree.

jfreeman74

johnnyph

that's too bad because the first pic is the envelope it came in and the return address is Pontiac headquarters in Michigan. It doesn't get any closer than that.

LAFireboyd

iTrader: (3)

It came from Pontiac? Now I'm really curious.

You said it was too big to attach here? Rescan it. When you do that, you can change the format and the size before you resave it.

N8MAN1068

i'd like to see that as well, because the 85 ta's had the most powerfull 305's (at least for autos anyways), so if 89 has more, then my 85 has more....

if ya can't scan it, can you fax it?

SweetS10v8

email me the pic. Ill figure out how to extract it.

rls96@aol.com

johnnyph

sorry haven't been around a computer for while. Gonna try and e-mail it to ya

steven90GTA

Those horsepower numbers are wrong the 305 never had 255HP the torque is right it must be a typo the turbo T/A had 250HP the 305 would not have more than that ever or the 350 with 240HP

Dante93GTZ

iTrader: (5)

Something is fishy here... We'd all be pulling 14's in the quarter STOCK with our 305s if that was true.

johnnyph

it was supposed to according to Hot Rod magazine. Same exact powertrain in a Z28 pulled 14.7@93 mph

Dante93GTZ

iTrader: (5)

A 350, I can see that. Maybe a 92 Z28 305 stripped out might pull that. Probably not stock.

TA

iTrader: (1)

My book shows '89 TPI 305 as 190 HP for Auto, 215 HP for Manual trans. (Firebird Redbook from Motorbooks international) I have no idea if this is accurate?!?

Troy
So Cal

Dante93GTZ

iTrader: (5)

That is close to accurate, if not so.

johnnyph

ya know what? You can all think what you want but so far no-one has any documentation frm the manufacturer. to prove otherwise. So if you say I'm wrong PROVE IT!!

Dante93GTZ

iTrader: (5)

We're (myself in particular) not trying to cause an argument, but these HP/TQ numbers have been thorougly covered on this board. I can see a 5-10hp +/- on certain cars, but that tech data is pretty damn close.

Prove to US otherwise. Run your stock 305 on a dyno and prove that its got that kind of HP. Run it down the track and prove its capable of consistent 14's in bone stock form as claimed by the shows/magazines you've seen.

SweetS10v8

If the 305 has that much HP, how much does the 350 have?

Doesnt the LT1 have 275hp? You know L98s arent out doing LT1s

speed88

A 305 TPI car DID NOT make 255hp from the factory. Plain and simple.

It is a proven fact on many respected thirdgen and GM websites that the fastest TPI cars from the factory in a thirdgen f-body shell were the L98 powered '91-'92's. There cars were rated at 245 hp. So how is it possible for a earlier year 305 to be making more??

You ask us to prove it?? Just look at all the documentation, and threads on this and other respected websites. I say why don't you prove to US that you have this documentation. Then I'll shut up!

steven90GTA

There is nothing to prove except that you have a paper that has typos on it, it is common knowledge that the 305's did not make that much power I say again the 305 in 89 would not make more power than the:hail:turbo T/A:hail: or the 350 from the factory, if so then you must have one of the rarest thirdgens ever created, a one of a kind.

SweetS10v8

<------ Still waiting on that email.......

pmpn

I think even 230 is too high in that table. How can 45 ci equal only 10hp??

mikobu3

pmpn

the reason why the 305 has 10 less than the 350 is because the tpi is no good for a 350 . the 350 tpi has more tourque , so off the line the 350 would win

to mention about modding a 305 tpi , well i just did and took it for a ride today , still not tuned properly , i was in a race with some young punk drivinf a chrysler 300 m looks like a 2002 at least , well he got left behind pretty good ,

what i;m saying is the reason why there was not much hp difference between the 305 and 350 was because the 350 tpi;s cannot breath ,and it was designed for a 305

hope nthis helps

1989GTATransAm

iTrader: (3)

OK I have the dealer catalog for 1989 Pontiacs. I picked one up when I bought my then brand spanking new 1989 GTA. Here are the high specs for the engines. This is from a Pontiac factory brochure from 1989.

5.0L...225HP and 295 lbs-ft of torque. Formula and GTA only.

5.7L...235HP and 330 lbs-ft of torque.

Hope this helps. Allen

johnnyph

Actually I have that catalog. You're right that is what it says. Hopefully SweetS10V8 can get this posted for you all. Honestly, every time I see any numbers for any of these cars it's different. Every horsepower number mentioned on this thread is correct according to this build sheet also. The only thing is, that it shows about four of five different 305 configurations. Also the 350 has a hell of a lot more torque than everything. Hopefully we can get this thing posted and you can all see what I'm talking about.

steven90GTA

No paper will prove that the 305 from 89 had more power than the Turbo T/A also from 89, and the 350 there was only 1 configuration they came with from the factory, the one listed here.

SweetS10v8

I got your email, but all i got was an empty folder. When I downloaded it, it was a .ink file. Has anyone heard of that before??

Anyways, Johhny I sent you intructions how to change it, but I just thought of an easier way.

Get the picture on the screen, then hit Ctrl + Print Scrn(just to the right of F12) buttons at the same time.

Now open up paint, powerpoint, or photoshop and paste it. You might have to open the picture program first, then hit "Cntrl + Print Scrn" then paste. Then be sure to save it as a jpg.

mjustdie

i have the 86 305 tpi setup in my iroc. the only year gm detuned the camaro. the #'s were the same as the birds. in 86 these engines had only 190 hp stock and only gained about 30 hp up until 92. the 350's always had at least 10+ hp over the 305's. to say that and bird had a 255hp 305 from stock, i can only say PROVE IT!!! I have been messing with these damn third gens for 6 years and never seen one with a higher output going to the 305 instead of the 350 from stock.

SweetS10v8

It has to be a misprint, says 305 has more power than a 350

LAFireboyd

iTrader: (3)

It's a typo. You can tell by the metric conversions of the US hp numbers, US being (in parenthesis). 153 and 153 for the (205hp) LB9s; 168 for the ("255"hp) LB9; and 179 for the (240hp) L98. The 168(higher than 153, lower than 179) is right in line with the others and should have an hp number higher than 205 but lower than 240--225hp. So someone just double-typed the 5 instead of the 2.

And comparing torque, 295 is also right where it should be compared to the other combos, which would again fall in line with an engine of around 225hp, not 255hp.

But this isn't anything on johnny. He only told us what he read from an official source, AND he showed us the source. So thanks for showing us johnny and Sweet.

jconrad

Weel at least we al have closure now...And see, even manufacturers can make an occasional typo.

johnnyph

THANK *** IT'S OVER!! and thanks for getting it posted sweet s10

SweetS10v8

not a problem