blown stroker small block??

[speedeamon]

Have a 2000 Dodge Ram and turning it into a street truck. Wife and I have decided to build up a blower motor to replace the stock engine (so when something happens to the HP motor I still have the stock motor to toss in). Is it possible to build a low compression engine(for use with a T-trim blower) utilizing the 4" crank? If so, any ideas on what pistons to use? Ideas here would be greatly appreciated!!

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2000 Ram reg cab short bed 5.9
Edelbrock stainless steel headers
true duals
Dynomax high flow cats
Flowmaster 40 delta series mufflers
Megs rolled edge oval stainless tips
Trans-go shift kit
B&M 28,000 gvw tranny cooler, hard lined in
Hughes 2500 HD stall converter
4.10 gears and Auburn posi
Best 1/4 mile times:
exhaust mods: 16.199 @84.29
exh. & tranny mods: 15.956 @85.03
exh, trans, rear mods: TBD (but much faster!!)

[sanborn]

Guess I am not very knowledgeable but what is a T-trim blower?

[speedeamon]

sanborn:
Vortech makes an S-trim blower for stock engines and a T-trim blower for modified engines. Just more flow and more pressure.

[rumblefish360]

I'd contact a piston manu. on what piston & compres. you should use with that blower.
Keep use updated on this. This sounds great.

[sanborn]

Please forgive me for my ignorance. I have been away from street blower motors for 25 years.

Blowers are great for the street, they look sexy, make a great whine with gear belts and when you push the loud pedal push you back in the seat. But, they are very hard on engines especially cranks and blocks.

Let me give an example. If you build a 400" engine with good heads it may put out 450-500 HP without the blower. So put a blower on and you can run it with good mileage,etc. But the first time you push the loud pedal the blower may put out 7-8 pounds of boost, suddenly you have 700 HP on tap but whats worse your torque also increases by 50% to about 650 ft lbs. Iron cranks can take that torque a finite number of times and then "Kapow". The same for stock blocks.

I would suggest you use at the very minimum a Mopar Performance forged steel crank with 360 journal size to get maximum journal overlap. An early 360 block may be OK. Try to bore it as little as possible to maintain block rigidity. An "R" block would be better. If you use iron heads you should "O" ring the block. If you use aluminum heads you should machine receiver groove in the heads. DO NOT use use full groove mains, they allow too much crank flex.

Please take this advice from an old *** who has done it before and would love to do it again.

[turbododge]

A lot depends on how much boost you will run, but I agree that you should use a forged crank, forged pistons, O-ring the block or heads, and not use full groove bearings. I would crossdrill the crank, however.

We are using turbos instead of a supercharger in our 340, but the effect is the same. We are running the above mods on a converted 4 bolt 340 with 8 to 1 compression and currently 14 psi boost on pump gas. We use head and main studs. The engine has been running for 13 years and has about 25,000 miles. We estimate in excess of 600 hp at 14 psi and it is still alive and kicking.

Early on we had head gasket problems, but the O-rings, copper gaskets, and the right sealers took care of that.

[speedeamon]

Sorry Guys, I've been out for the weekend. Since bottom end strength is most important, is the MP 360 crank stronger than the stroker crank?? Is it more important to stay with a stronger crank with less cubes?? I haven't looked yet, but is there a 4 bolt main 360 block? Thanks for all the input and look forward to more info.

------------------
2000 Ram reg cab short bed 5.9
Edelbrock stainless steel headers
true duals
Dynomax high flow cats
Flowmaster 40 delta series mufflers
Megs rolled edge oval stainless tips
Trans-go shift kit
B&M 28,000 gvw tranny cooler, hard lined in
Hughes 2500 HD stall converter
4.10 gears and Auburn posi
Best 1/4 mile times:
exhaust mods: 16.199 @84.29
exh. & tranny mods: 15.956 @85.03
exh, trans, rear mods: TBD (but much faster!!)

[sanborn]

I assume the T-belt blower is a gear belt blower. If it is it has full effect at all rpms versus a turbo that doesn't have much effect at low rpm but really comes in at high rpm.

The torsional stress on a crank is highest at low rpm. As the rpm rises the rate of stress increase actually declines. Launching from the line creates a lot of shock on the crank in the form of torsional stress as well. That's the reason you want maximum crank journal overlap. The shortest stroke has the maximum overlap thus is the most rigid. So the safest is the 360 MP steel crank; but, the stroker is sexier. It all depends on how you will use it. If it was an all out engine you would want an all out 4340 billet (big$). I would lean toward the stroker.

I haven't checked but I am pretty sure there is an "R" block with 360 journal size.

I don't want to beat this subject to death but as a comparison the Nascar truck engines use main bearings of 2.250" and rod journals of either 2" or 1.88". They can get away with this because they have no shock load and their rpm never drops below 6000. But a crank like this would come apart in an application like yours.

[rumblefish360]

M.P. has a upgraded 360 crank, but it's still casr. They also have a billet crank ($$$) The other cranks offered are forged.