small Block chevy HP tips

[Anonymous]

So what are the little tricks for more hp.
I have been told serpentine belt not v belts
for dd duel plane intake
also what cid is a 400 30 over.

 

[bondsman]

to determine displacement the formula is i might get this wrong it has been awhile. bore x bore x .7854 x stroke x # of cyllinders =.

 

[Waterthunder]

A 400SBC bored .030 over will have a bore of 4.155 and a stroke of 3.75 this will give you 406 cui. If your motor is standard now I would recommend boring it .010 because you can find a shelf piston. The bores are close together on a 400 and your better off with more material between the bores. If you only go .010 over you will have a 402.8 cubic inch motor. If you are not willing to do a cam change at least install 1.6 ratio rocker arms this will increase your valve velocity and improve bottom end torque and snap. If you do want a cam change on a DD motor I recommend a cam on a 106 lobe center.

 

[Anonymous]

I have 1.5 rollers on it with 202 fueleys
The motor is built from parts I had left around. I will probably start building one of the other 350 motors just to have one ready. I have no idea how long they last on a boat. I would like to say this motor is only around 350 hp I would have to check the cam specs. what i dont know is what hp i generate at 3 thou. Its also been over 15 years sience i built motors.
And i never built them for low RPM period The cams i am use to dont start making power untill 4 thousand RPM

 

[spooledup50]

i built my sbc 350 from scatch for low rpm power it has new cast iron vortec heads 98 models and 98 model roller lifter cam from a truck with 6 degrees of advance in the cam 1.65 ratio roller rockers edbrock performer rpm dp intake and a 500 cfm edelbrock carb oh and 11.5 to 1 speed pro hyperutetic pisons <the are liter in weight>i can swing a 5 blade 68 inch warpdrive with 16 degres of pitch 3100 but curently run a 78/32 wide blade direct drive florida air props says thats about 300 hp at 3000 rpm or 540 # torque at 3000 pretty good for sbc dd huh just have to build the right combo mine works like an 0540 and it was alot cheaper and i got about 200 hrs no probs

 

[Anonymous]

That is over 1.5 foot-pounds per cubic inch. That is almost unheard of.

 

[Waterthunder]

I believe this motor get's it's torque from lot's and lot's of cylinder pressure. If the motor is over 11:1 with a stock cam and the cam is advanced 6 degrees this motor probably has over 240LBs of cylinder pressure. If all this info is true it should be a beast but with iron heads it's right on the border of burning a piston. The higher ratio rockers also give it good valve velocity so it will have snap and torque.

 

[COLD]

I can't help :lol: but saying 8) it sounds like a blast! :lol: Let's see! :lol: 489cidX1.5 = 733 TQ ? :lol:

 

[Waterthunder]

Sounds good on paper but it don't exactly work like that. A 496 is a good motor but a good small block with a gearbox will smoke it. And if you want to run a big block run a gearbox if ya can. When you put a huge load on a motor at low RPM's your cylinder pressures and temps hit the upper limits. The problem with making power and torque at 3000rpm is there are only two ways to do it with a gas engine either cubic inches or cylinder pressure.

 

[COLD]

Not exacly expecting 733 but 10/1 489 Vortec shouldn't be totally boring to a newbie. Looks like comp cams sugestion bleeds off a little pressure and peaks torque at 2800. Very helpful bunch who you can discuss diferent ideas with. Thank's Comp!

 

[Waterthunder]

I send everybody to comp. We have been working together on all my LS1 grinds for some time now. See on paper the smaller cam will build more torque. And if you build a motor on desk top dyno which I know 1/2 the car motor guy's do the combo that gives you the most HP and torque can not be built in the real world because the motor can not sustain them kind of cylinder pressures. You can come up with some crazy stuff on them dyno programs trust me ten years ago I was playing with that dyno every day however those 700ft pound torque combos at 3000RPM's only work on the computer.

 

[spooledup50]

have you ever tried the people at kam motion in louesanna they are great custom cams are back to ya reel quick i use them for all the race car engenes and reduction drive engines i build were talking from 800 to 1600hp motors there small but good people give the little guy a chance

 

[COLD]

Do you have a link or phone number for them! 8)

 

[Waterthunder]

I used them ten or so years ago when they were involved with Wayne County Speed Shop and Darrel Alderman. Out of everybody I have ever used Comp has em all beat with service and grinds they by far have the most agressive lobe profiles.