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garrell.770 08-05-2012 04:36 PM

Need a horsepower estimate please
 
Not sure I came to the correct dept. but I need to describe my engine to the best I can and I know some of you will know about how much hp it is making:
1970 standard bore 350 ci. 4 bolt main block.
Flattop forged high compression pistons, with two valve reliefs.
64 cc combustion chamber Vortec heads.
Comp Cams Magnum 270/470 cam with lifters kit
Edelbrock polished medium height intake manifold.
Carter AFB Competition plus 725, I think, cfms.
Sanderson streetrod headers ran open all the time at the collectors
Not sure about the valve size but the engine has lots of compresion, I am guessing 10.5 to 1 and I think maybe around 340 HP?
It is in my 37 Chevy hotrod truck. It jumps at the slightest touch of the accelerator. The truck weighs 1740 lbs. with me in it and cranks faster than any electronic fuel injection automobile we have warm or after sitting five days.
Any estimates of hp will be apreciated.

Garrell Patterson

vinniekq2 08-05-2012 07:58 PM

ya,300 plus or minus

2wld4u 08-05-2012 08:02 PM

well Id say your making 360-375hp :)

garrell.770 08-05-2012 08:35 PM

Need a horsepower estimate
 
There is not much else info I can give the crankshaft is a standard length for a 350 as is the bore That I had already described in my original thread. I am just guessing but I think at least 330 to 340 but I wanted the opinion of what I know are a lot of experts in the forum that may have even dynoed engines after putting them together,
Oh yeah we did a little porting and polishing up on the heads, not a profesional job just a little shade tree work done in the shop in front of a airconditioner.
I have an old Mustang rack used in conjuction with the original straight axle. The truck will go a lot faster than I want to drive it with current setup but it sounds good at trafic lights and gets lots of thumbsup.
Any more opinions are really appreciated and a 1/4 mile et and approximate speed will be welcomed also. The truck has a turbo 350 transmission, I don't know the rear gear ratio but from experience it is positraction unit probably 3:53 on the low estimate and 3:73 the lowest.
Thanks

Garrell

vinniekq2 08-05-2012 08:41 PM

whats the truck weigh? whats the redline of your engine?
for comparison a 370 hp GM 350 came with 11;1 cr,solid cam,2.02 heads,aluminum intake,780 holley.

ap72 08-05-2012 09:18 PM

If its tuned really well your estimate sounds very reasonable. Et's depend on a lot of other factors but mid 11's wouldn't surprise me.

garrell.770 08-06-2012 04:07 AM

Need horsepower estimate
 
ap72 thanks to you and everyone that offered opinions so far. I know engines and there buildup fairly good and I felt like my 340 hp estimate was reasonably close but I had rather have opinions from the experts out there.
The truck is always kept in good tune. It has a HEI ignition with I forget the size of the sparkplug wires but they are the heaviest offered I think and we have looms attached under the edge of the valve covers and there are no wires laying across the headers. The carb on the truck is the best I have ever been around it hasn't been adjusted since the day I put it on. It has an electronic choke which never has to be set. It can set for five weeks and you depress the accelarator a half inch and you never hear the motor turn over it as if it explodes to life. Once it is cranked it cranks all day long day after day without touching the accelarator. The truck never falters or boggs down, I don't know what the readline should be, a safe number would be 5,000 rpms with a max of maybe 6,000 if I had reason to take it that far.
As far as an et I don't know what he rear gear ratio is I don't think higher than 3:53 or lower than 3:73 as I stated in an earlier post. I know the hp to weight ratio is really good but I figured maybe low 13's or high 12's.
I would still like opinions from any of you or suggestions to make the hotrod better, you can't believe how little I have in the entire rig to wind up being a pretty good high performance ride. Sometime I will tell you about the local big car show a few weeks ago and the five over $100,000.00 that debuted at it!

Garrell

454C10 08-06-2012 05:13 AM

340 seems about right with gm heads. 375 with a better set of heads.


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