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Discussion Starter · #1 ·
I am thinking of building a 334 stroker (stroked 305), and i want to know if it can be safely supercharged at 5 psi if the engine has 9.6:1 compression, and 4 bolt mains, or if it would kill it? I want it to last at least 70,000 miles.
 

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Look at some blower drive charts, that's going to put your cylinder pressure sky high, equivilant to maybe 13 or 14:1 or more. You going to "O" ring it and use forged parts? What heads?

Some of the experienced blower guys here can share a lot more experience than I have.
 

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Discussion Starter · #3 ·
I didn't really want to mix and match kits, and the stroker kit I want has 9.6:1 compression with 64cc heads. I will be using GM vortech 64cc heads on the engine. I just wanted to know if there was some way I could put forced induction into the engine and have it be safe. Maybe using 74cc heads?? And the kit i am getting comes with all forged high quality parts...it's a more pricey kit, so it can handle some abuse.
 

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You can either put dish pistons or 76cc heads on the engine to get around 8.5:1. Even with 9.5:1 you should be fine with boost 10-12 psi boost on pump gas. I have to say that all the media is mostly wrong on what the limits of pump gas are in relation to boost. I know of many cars running 20psi or more on pump gas. Now if you read all the crap out there you will see that according to the magazine experts 10-12 psi is just the ragged edge.....I have to laugh we I read that.

I went for a ride in a truck a few weeks ago running 23psi on straight pump gas with water injection when boost comes on to prevent detonation.

Point is, you will be fine with boost on that engine. Lower compression would be better, but you can still run a decent amount of boost with 9.5:1.

Chris
 

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What kind of supercharger? This will make all the difference in the world.

If you are building the engine and plan on running boost, Why not do it right? 9.6:1 is not the way to go (depending on what kind of supercharger). Are you running iron or aluminum heads?

Give more info on your plans and maybe we can get you headed in the right direction.

12lbs of boost from a roots supercharger is not the same as 12lbs from a centrif or turbo.

Royce
 

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And plug temp plays a very important roll in how a blower works. I hate to admit it but I lost a 400 SBC from running too hot of a plug once.:drunk:
 

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I am sure you dont want to hear it, but if you built a 383 with AFR 195cc heads with 10.5:1 compression and no supercharger, and got rid of the 305, you would make more hp than a stroked 305 with a supercharger. The main problem on the 305 is the heads. They are worthless. If you are serious about making power, I would go with a 350 based motor.

Good luck,
Adam
 

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Discussion Starter · #8 ·
I would either run a vortech type supercharger, or go with a turbo, and I would be using iron GM vortech heads. A friend who installs turbos and superchargers said HP numbers would be around 550 to the wheels with about 8-10 psi with this setup, and he knows his stuff. I really don't care to make any more than this for HP.
 

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I am not trying to argue with you or put your stuff down, I just want to make you get the best bang for your buck. Think about this; I did a little research, and the most powerful 305 that I could find that was used in a firebird was in the 1987 firebird, it had 205 hp. Lets assume that it would continue to make that hp/cubic inch in a 334, that would put it at 230 hp. Now, if you got new vortec heads, a new cam/intake/carb/ignition, and exhaust, lets give the 334 the benefit of the doubt and say that you would gain 100 hp and ignore the fact that you would have to drop the compression in order to run 8-12 lbs of boost to around 9:1 at most. That puts you at 330 hp before the supercharger. At 8-12 lbs of boost you could get as much as a 50% gain in hp, lets say that happens. In this case, you are looking at 495 hp at the motor. If you assume a 20% loss to the rear wheels, that would be 400 rear wheel hp. This power can easily be attained with a unsupercharged 383 with a good set of heads and a matched combonation. Then, you have parts that can be used in the future if you want to go faster. With the 305 motor, the motor is maxed out.

Just trying to help
Adam
 

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One problem with your theory, Adam. He can run much more boost than that to get the power he wants. With turbo or centrifugal supercharger and water injection he can get 20 psi or better on pump gas. That said, it would still make more power with more cubes, so....
 

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Thats right, water injection will go a long way towards getting rid of detonation. If he wants to do that, he will be able to get more hp out of the motor. I am currently in the process of building a 9.0:1 358 with 30-35 lbs of boost through an F2 procharger with water injection. But I am also running an air to water intercooler, 118 octane fuel, and aluminum heads. Still, with the lack of flow associated with the 305 heads, especially on the exhaust side will the small size and low flow of the heads make it ineffecient to run alot of boost? (more than around 15 lbs?)

Adam
 

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Wow, 30+ psi should make monster. Hope you have a retired prostock chassis to put that thing in. Should make 12-1500HP or so I guess.

If he goes turbo, the exhaust port size should not be a problem. I would just smooth up the ports a bit and clean the bowl to make for good velocity. With a supercharger, it would be restrictive for sure without some work.

Chris
 

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The biggest problems I see with 305 based blower motor is the lack of pistons made for blower use. There are several off the shelf blower pistons for 350 based motors. Any good blower piston for a 305 based motor is going to be a custom piece. Most any good piston can take 5 psi boost but boost is addictive, once you try 5psi you'll want to try 10 psi, then 15 psi, etc.
Also all the good heads are designed for a 4 inch or larger bore.
 

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Turbo, I just wondered if you have ever talked to anyone running a F2 procharger, and if so, did they like it? 1200-1500 is actually exactly what I am looking for. The car is going to be run in a outlaw 10.5 class, I am hoping for low 8's. The car is a 1969 firebird that weighs 3000 lbs without the driver. I am running AFR comp package 220 heads with extra porting from Rehr Morrison, and the other specs are shown above, do you think 1500 hp at the motor is an attainable goal?

Thanks
Adam
 

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I have to agree the heads will be the major problem with a supercharger or even a turbo. If the engine can't get the bad gas out it can't get a fresh charge in. While I don't doubt you can make 500HP with a 305 I just thin you are fighting losing battle. Leave everything the same except make that engine a 350 (or larger) and it is a win- win situation. The small bore on the 305 just really hurts your cylinder head options.

firestone,
Sounds like you are building a monster. What kind of block and cubic inches are you thinking about?

Royce
 

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Never talked to anyone running the procharger, but have seen some on the net. They seem to make very good power, which anything with boost will. I have to also agree that the heads are going to be limited, but I dont think it dooms the project.

If you dont already have a 305 for this project with money spent, the 350 would not be a bad idea. If you have already spent alot of money on what you have, you can make good power with the 305.

Chris
 

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Discussion Starter · #20 ·
Are you saying the stock heads make the project lmited in the power it will make, or the vortech heads make it limited (1.94/1.50) becaue thats the head I'm using. And I do already have a very nice 305 engine and cam and roller rockers for it, although those can be universal between all SBC's. I just don't have the extra money for a new 350 block, and all I want is around 450-500 to the wheels. I think it can be done.
 
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