Horsepower and Toruqe Q's

[GrandeStang73]

I have just built a 71 or 72 351C 4V, cant really find the part numbers. I have put the motor together and was wondering how much power it will be making based on what it has in it. Its been bored .060 with aluminum flat-tops, .572 crane cam with a ferra valve set. Edelbrock aluminum dual plane intake with a 650 cfm thunder series carb. The only other thing is a set of Hooker long tube headers. I kept the all around specs with horsepower and torque. Just want to compare and see what kind of power I might be making.

 

[D.Hearne]

Quench heads or open chambered?

 

[GrandeStang73]

Quench Heads I do believe, can you give me opinions on both please? Id like to see all the options Thanks!

 

[D.Hearne]

You should be somewhere between 400 and 450 hp. The only part that would limit you (on top) would be that carb.

 

[GrandeStang73]

Yeah, I figured that out... I set it up for open chamber heads. Which that should be alright for. If they do turn out to be quench heads, ill need to change it out, just due to the compression boost of those heads. Thanks for the input! Im happy with those numbers....... for now

 

[tylerrocks]

wow, I dont know much about 351C's, but those are nice numbers IMO considering the parts given. I guess those C heads were good stuff, eh?

 

[ratio411]

I think it would be around 350 myself.
Also, the heads need rpm, I don't understand putting such a mild intake and carb on heads that need to breathe to make power.
I think 350 FWHP max.
Just my opinion, I am no dyno.
Dave

 

[ratio411]

Also, if the engine is really a 71 or 72, you have about a 25% chance of having the closed chamber heads. They were discontinued mid-71.
You need to know/disclose quite a bit more info to get a good idea of what you have.

 

[dodgestang]

Yeah, I figured that out... I set it up for open chamber heads. Which that should be alright for. If they do turn out to be quench heads, ill need to change it out, just due to the compression boost of those heads. Thanks for the input! Im happy with those numbers....... for now

What numbers? The first swag of 400-450 HP?

Do disrespect meant but...dream on and drink some more cool aid. If you want to know how much power you are making go to the dyno. You will be surprised to put it mildly. You would be extremely lucky if you were even close to 300 RWHP with the combo as you have described it. Stick tranny....closer to 300....auto tranny....further from 300.

But then again....that's just my opinion.

Also, if you set it up for open chamber and then put closed chamber on there....what compression did you set it up for initially? 10.5:1? IF you did....you now have a ticking time bomb at 13+ compression

 

[fast4cheap]

I have built many clevlands, maybe 320 flywheel with open chambers maybe 340 or 350 flywheel horsepower if they are closed, I would bet on it, Unless you are using a Austrailian block 0.60 over will probally cause a heating problem. clevlands make alot of power but not with dual plane intakes and 650 carbs. The only dual plane I have ever seen make power on a cleveland is made by blue thunder, it cost alot. If it makes 400-450 horsepower start looking for a hidden nitrous bottle.

 

[Hack]

I have read about a number of Cleveland builds that make honest to goodness 400-600+ horsepower, but that is only when all of the parts are picked out to work with each other. 4V CC heads (and OC heads for that matter) can make a lot of power, but if you choke them with a small carb or your timing is wrong or if your cam doesn't match everything else or...

Any one thing that is wrong and you'll make less than 300. It's not easy to make 1 hp per cube or more. The engine has to be spinning to 5-6,000 or more rpm, for one.

I would be surprised similar to Dodgestang if this engine even makes 300, mostly based on your lack of knowledge of what you have as well as the small carb which will limit your upper end power. You need a lot more carb to get more HP. Possibly the engine is extremely well set up, but not likely IMO.

My advice is: just drive the car and if you like it, be happy. I would recommend against trying to make a ton of power in a 0.060" over Cleveland, though. If you didn't have the block sonic checked IMO you should keep the 650 carb and if you decide to change anything keep everything mild.

 

[mustangdave]

.060 That is all.

 

[D.Hearne]

I based my guess on two things. I have seen one Cleveland build using 2 bbl open heads and a similar cam that was a tad over 400 on a dyno (FWHP) I did not take into account the too small carb. The build I saw also had an Edelbrock Performer intake.