408 Stroker

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Motor work ind. Out of spokane wa are the ones who built this motor.
 
I wanted and was expecting 520hp and 500+ trq but anything over 500 i would be happy with. This is my first engine build so i was not sure what to expect.
ou812 said:
Did it make the power they said it would? Are you happy? Did you get what you paid for?
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I would put it in the car and see how you like it. If you're happy, GREAT!...however; I would be looking for answers for the lost hp...but then again, I built my motor so that if something went wrong I would be the only one to blame.
 
I think i found the one problem they went with the wrong cam.
I said match the specs to the Big mutha thumper witch are:

Lift @ .50 INT 243 EXH 257 Valve lift INT 533 EXH 519

I got the mutha thump Lift @.50 INT 235 EXH 249 Valve lift INT 522 EXH 509

Would that make that big of a difference.
 
I still think you'll need a different cam than the Big Mutha Thumper. Like has been mentioned earlier in the thread; that cam is for the muscle car sound/lope. It's to resemble '60's and '70's cams. I think you'll only get maybe 20 HP, if that, by switching to Big Mutha. It depends on what you want. Don't get me wrong, the power you're making isn't bad at all, and it seems like you posted that you have $5K into it. Your HP to dollar ratio isn't bad at all. There are some who spent more and got less power, or got only slightly more. I can tell you this; you have me smoked on the HP per dollar ratio!
 
64physhy said:
....... like you posted that you have $5K into it. Your HP to dollar ratio isn't bad at all. There are some who spent more and got less power, or got only slightly more......
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Exactly! You get what you pay for....only 5k and you have a nice thumpin motor. Speed is money, how fast do you want to go?
 
If this is a street car I think you've done very well. It's going to fry the tires anyway so more power is really a waste. But if you want to upgrade later why not. A cam with 255* at .050 and around .575 lift would be a good choice. A single plain intake, big 4150 carb and bigger headers, at least 1.875 will step it up considerably. This may require a looser converter though so there goes some streetability, but if it's just a weekend car so what.

I'd run it like it is, hell if you didn't have it dynoed you would have never known the difference anyway. :)
 
if it driven on the street a couple times a week it a nice build . torque gets the car rollin or burning the tires, later you could do like guitar jones says is change to more aggressive cam/convertor, victor intake, bigger carb, it will run 10s with traction.
 
scampmehard said:
I think i found the one problem they went with the wrong cam.
I said match the specs to the Big mutha thumper witch are:

Lift @ .50 INT 243 EXH 257 Valve lift INT 533 EXH 519

I got the mutha thump Lift @.50 INT 235 EXH 249 Valve lift INT 522 EXH 509

Would that make that big of a difference.
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It's going to make a difference but not tremendous. I have read 2 guys here tout how so and so makes power with the Mutha thumper cam. I have a question, which mutha thumper cam? There ain't just one. The smallest to the biggest is a big difference. If I'm not mistaken you've got the smallest one, which is pretty small for a stroker but it sure does make some nice low end and mid range torque. Personally I like the looks of the numbers. Especially if it's a street engine. I wouldn't get all hung up on the numbers and run it. I bet it'll put a huge grin on your face from ear to ear when you stomp on it.

BTW: you can't just install 800 jets in a 750 carb and make it an 800. The # 750 or 800 is the cfm of air flow rating. Jets don't affect that.
 
fishy68 said:
It's going to make a difference but not tremendous. I have read 2 guys here tout how so and so makes power with the Mutha thumper cam. I have a question, which mutha thumper cam? There ain't just one. The smallest to the biggest is a big difference. If I'm not mistaken you've got the smallest one, which is pretty small for a stroker but it sure does make some nice low end and mid range torque. Personally I like the looks of the numbers. Especially if it's a street engine. I wouldn't get all hung up on the numbers and run it. I bet it'll put a huge grin on your face from ear to ear when you stomp on it.

BTW: you can't just install 800 jets in a 750 carb and make it an 800. The # 750 or 800 is the cfm of air flow rating. Jets don't affect that.
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The Mutha Thumpr line is sized by name i.e. Thumpr, Mutha Thumpr, Big Mutha Thumpr.
 
The BSFCs seem a little high and I'd be questioning the porting before anything else. A smaller cam, with a good port, will make as much power as a mediocre port with a bigger cam. The BSFCs say you're using a little more fuel than I would think necessary to make what you're making for power. Especially seeing that you have to jet the 750 up so much. So why is the question. IMO based on info given, it's in the heads. I dislike the Thumper line because it's designed to make noise, not power. Plus, with the hydraulic rollers, you lose more lift because of the pushrod angle. You have to design that into any cam choice. Similar 4" engines I've built even using a flat tappet hydraulic and ported factory heads with less lift make another 30hp. Something is amiss. But I'll add those engines have between $1K and $2K more in them. So for the cash spent, you got a good solid result. It's not a level of performance I would be disappointed about. for $5K. Did you get a flow sheet with the heads?
 
Most likely it's the cam that is holding it back. Like mentioned, something in the 250* range and 550 lift is what it needs. Looks at some of the recent builds that approach 500hp, not many, if any have a cam with duration/lift that short.

If the heads were ported and they did a bad job on it, that could hurt as well. Those heads with nothing but a 2.02 installed and blending the throat cut are capable of 520hp with the proper compliment of parts.

The headers might cost 6-8hp compared to a tti or supercomp/hussler. Not a good gain for the dollars you'll spend to go another direction. IMO, better money spent elsewhere.

Don't get sucked in by dyno numbers. I know some guys that "know" big numbers sell engines. Those same mills don't seem to run like a lower HP engine MPH at the track. It's pretty commonplace in the world today, like "my dad can beat up yours" or "my johnson is bigger than yours", etc. Proof is when they run the MPH at the track and I've seen PLENTY of disappointed people over the years. Just watch pass time and the 700hp cars that run mid-high 120 mph ranges at 3200-3400 pounds... ummmm yeah right 700+ hp LMAO, NOT A CHANCE.
 
Big flat tappet/roller would be nice.That 4 inch arm yanks hard on an intake port.You need to feed it more cam timing.Brians on the money.
 
You mean if I stroke my little 340 it still would not make 700 hp, gee wizz....but it has too, after all its quicker than new 450 hp vettes and weights more, LOL


(how these HP ratings are done today i have no freaking idea, something must be in the koolaid):sleepy3:
 
Chuckbizkits said:
Obviously you cats are sorely mistaken about the Comp thumpr series. Wazoo is making 550+ with one. With a 750 cfm carb, no less.
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Just because one makes that power doesn't mean all will, as in the case with the OP's engine. If they are all that good why doesn't his make 550 hp? It's all in the combination that's why. Sometimes you get lucky and hit the nail right on the head and sometimes you hit it off the side a little. Sometimes you miss it all together.
 
the cam is not hyd it is a soild/roller it was grind to match the Big mutha thumper specs. Im still waith on my build **** for exact details they told me the way the port and polish is they gasket match and cut out all the metal they can as possably aloud. The carb was just one they has sitting around it is not the carb im going with..


moper said:
The BSFCs seem a little high and I'd be questioning the porting before anything else. A smaller cam, with a good port, will make as much power as a mediocre port with a bigger cam. The BSFCs say you're using a little more fuel than I would think necessary to make what you're making for power. Especially seeing that you have to jet the 750 up so much. So why is the question. IMO based on info given, it's in the heads. I dislike the Thumper line because it's designed to make noise, not power. Plus, with the hydraulic rollers, you lose more lift because of the pushrod angle. You have to design that into any cam choice. Similar 4" engines I've built even using a flat tappet hydraulic and ported factory heads with less lift make another 30hp. Something is amiss. But I'll add those engines have between $1K and $2K more in them. So for the cash spent, you got a good solid result. It's not a level of performance I would be disappointed about. for $5K. Did you get a flow sheet with the heads?
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this is going to be my daily driver for the summer so it is a street machine and weekend drag car.
 
as far as headers 1 3/4 or 1 7/8 money not a issue and ill be running 3" oval with h pipe spin tech dummping out the side of the doors. Im liking the TTI the best.
 
scampmehard said:
as far as headers 1 3/4 or 1 7/8 money not a issue and ill be running 3" oval with h pipe spin tech dummping out the side of the doors. Im liking the TTI the best.
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Yeah, just go with the TTi's. For what you're running, they will definitely do the job. Dougs would also work. IMO, you really don't need the 1 7/8" for your combo.
 
I was think 1 7/8 for future use but how much hp wil 1 3/4 be good for?
64physhy said:
Yeah, just go with the TTi's. For what you're running, they will definitely do the job. Dougs would also work. IMO, you really don't need the 1 7/8" for your combo.
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