Does anyone know how much HP the stock bottom end of a 1991 F-Body 305 can handle?

I was told 400 HP MAX.

Thanks.

 

it's actually 401.6666666. or maybe, just maybe there is no certain number since it is a mechanical device and it only takes the weekest link to fail. you can be certain many will hold up over 400hp, and some will fail at under it. although, maybe if you check the library there is a book with a dead on hp limitation and if you go over it all 305's will give up....?

 

I will let you know in about a month. I should have " Project 400hp 305 " done by then. It is a beauty with 150k on the short block.

 

OK

So the fun begins!

I would like some real world advise on how much HP to bring the stock bottom end of a 305.

Plus or minus OK.

If anyone knows some numbers on what it might be rated at, please post.

I am currently at 343 RWHP and have much potential for more HP. Just don't want to blow her up!

Thanks.

 

Tommyboy,

Do you still have the stock crank, rods, and pistons?

 

Hell Yeah !!!!
The way I look at is, the short block is not worth more than $50, so I might as well throw some parts at it and beat the hell out of it until I can put the 350 together. The only down fall is that I will have a little bit of money in the heads and if I throw a rod the heads will more than likely be junk. But on the same token they are 081's and I will be running Pro Action 235's when I build the 350.

 

Ha! Go for it.

 

What is your combo? Just curious.

 

Very simple......

SLP headers and 3" exhaust
Crane Cam
SLP intake runners
SLP air foil
SLP High Performance chip
Crane roller rockers
TPIS big mouth intake
Accel 23# injectors
GM stock Fuel Pressure Regulator
Racetronix high flow/pressure fuel pump and wiring harness
ATI Booster Pump
New fuel filter
All new ignition items (wires, cap, rotor, etc)
Jacob's Pro Street Ignition
ATI FMU
MSD Boost Timimg Retard Box


Oh and a ProCharger D-1SC with 10 # Pulley!

 

mine took 230 horse before it blew up lol

thats factory boys

 

OUCH!!!!

Need some good news here people!!!!

 

That’s a huge intake runner. You plan on spinning the engine to 9000rpm.

But for the 305 I don't know about hp limits but a member here, Willie, is trapping at nearly 118 in the 1/4. He is running stock crank and rods, but has forged pistons. Depending on car weight that some serious hp.

 

If you've done a good port, polish, and valve enlargement job on the 081s then they will work very well on a 350, too.

No kidding.

 

misterjuice i believe is also pushing 400+ hp on his 88 iroc with 305, might wanna try contacting him or next time i talk to him i'll lead him toward this thread

 

Are you sure Willie still has the stock crank and rods???

I would think the cast crank and rods would be the first thing to go out??

Thanks for the plug to MisterrJuice.

 

Says on his website that he is running the stock crank and rods.

http://members.optushome.com.au/iroc.../willies87.htm

 

I have a friend with a 92' RS, stock bottom end w/ 140K, stock t-5, and stock read end with a 4:56 gear. Put some eairlier model 350 heads, that were home ported, along with a edelbrock intake and a holley 650 carb and shorty headers. We dyno'd it on a chassis dyno, and it made 375 RWHP. Oh, and he sprayed 150 on top of that. All together he ran it for two years like that, and *** knows how many track and street beatings. Now he's got a little better combo.

 

Well that is some interesting news.

I am at 343 RWHP and would like to spray a 35 HP or 50 HP shot.

Sounds like this might work!

Any other experiences?

 

Something seems wrong here. Only 343 rwhp with that engine and 10# of boost? And you're asking if your engine could hold over 400hp when you're already making over 400?

 

It doesn't look like he has done much to the 305 itself. Just added bolt ons and done tunning. Of course added the Procharger to it. I don't know that he would have more than 343HP. But there is room for more potential in there.

 

A cam isn't really a "bolt on." Oh wait.. stock heads? What transmission?

 

Hi rezinn,

Well to clarify. I was meaning 400 RWHP. You are correct that I am at about 400 FWHP.

Hi 87WS6,

Yea. Lots of bolt ons and valve train work. Probably over $10,000 with the supercharger!

Unfortunately though looks like I will be posting on the Detailing board for some time.

I was just advised by Robert Kennedy who does dyno work, superchargers, nitrous, alky/water injection, etc. that I am at my safe limit with the stock bottom end.

So I will be driving her as is.

Of course I will still be playing with improvements to tuning. Such as a new Ram Air hood for which I am going to fabricate a custom intake to get cooler air to the ProCharger.

 

Yea. The stock heads are killing me!

Power drops off at the typical end point of 4500 RPM for the TPI cars.

Wonder how much I would gain with a set of World Products S/R Torquer Cylinder Heads?

 

May as well port your stock heads rather than buying a newer casting that is about the same. Or buy some performance heads.

 

What kind of performance heads would work on a 305???

 

Aluminum L98s are a popular one on 305s. Lots of potential if ported.

 

Yes Sir, Port them Stock Heads. I am porting mine as we speak and according to Sitting Bull and F-Bird they will out flow Vortec's, but you will need to install 1.94 Intake valves. I will bet that just by doing this that you will pick up at least 50 HP if not more, due to the SC.

 

I've heard that those are comprable to the World Products heads.

Actually now that I recall, Willie used Air Flow Research 190 Heads.

This would probably be the best for me since I have been following his set up.

Just did not want to get into a head change.

Do you think it would give much gains?

 

I saw your dyno graph on the power adder board. Assuming you have an auto your 343.9rwhp is roughly 429 flywheel (assuming 20% loss).

I'm wondering what you hp was before the supercharger? Any dynos of that, or at least a guestimate?

The more free flowing the heads are the more air you will get in there, which means more fuel, which means more power. Remember boost is just a measurement of restriction. Get better flowing heads on there and you current 10lb pully (8lb boost shown) will be producing less boost. In other words, the heads will make a good difference.

What Crane cam are you using? p# 104224?

Thanks

Robert

 

Yea. I understand you completely.

I have a Crane cam # 2032.

Stock FWHP for my car is 220. Car has a T5 tranny.

No dyno runs prior to the SC.

But the D-1SC is supposed to produce a 60% + HP gain.

I would expect that was my gain. So you can figure my previous HP.