Rear end build advice

[JayBar]

Originally Posted by Cashburn

Should be more than that.... but 500hp is at the crank. As most engines are sold

Casbburn, you are a knowledgeable guy, how can you say that a 351 with AFR heads and a lopy cam will produce 500 plus hp even on an engine stand with the builders headers and no accessories? Maybe with a 150 hp shot of NOS.

Engine builders may sell them with crank ratings for HP and torque, but we all know (or should) that everything changes when we put on the cobra headers and mufflers and normal engine accessories. Then there is the power train loss, 18 to 20 %.
I stand by my 300to 350 number mounted in the BDR. Would love to have your customer share his dyno readings once everything is installed.

Then again I met a Cobra guy who was told a 500 plus hp number, but always had an excuse for not putting it on a dyno to find the real number.
Down deep inside he would rather believe (and boast) the 500hp number than learn the truth.

[Whiplash]

Jaybar,

I was interested in getting as much advice as possible. I am sure there will be a redux at the rear wheels. And when I get my car, I'll be happy to dyno it and share the results if people are interested.

That being said, let's not make this about anything other than having fun and building cars that help us get there.

My figure wasn't a boast by any means just a stated figure from a build sheet so folks knew what it was I was shooting for. I was looking for advice about gear ratios from people that have had a set up just like mine, as it appeares you have. I appreciate the input.

[RMHINC]

I have BDR # 435. Jay & Brian @ Vintage built my car.You are in good hands as these guys are the best.My car Has a Performance Engineering 351w.It made 435 hp on the dyno. I don't know what the rear wheel HP is but I can tell you it is CRAZY FAST!!!!!. I have the 3:46 rear with a TKO 600 trans.5th gear is a little low but it is also nice to cruise on the Parkway( 70 MPH @ 2200-2300 RPM) So welcome to the BDR and Vintage family and I hope you have lots of safe miles. The fun, cool stuff, driving and ear to ear smile just come with having a Cobra.

[Cashburn]

Originally Posted by JayBar

Casbburn, you are a knowledgeable guy, how can you say that a 351 with AFR heads and a lopy cam will produce 500 plus hp even on an engine stand with the builders headers and no accessories? Maybe with a 150 hp shot of NOS.

I cannot say that, nor did I. The target is 500hp (I was simply cuing Sean's number), in reality it will likely be 485HP to make the thing run ok on poor CA 91 Octane and do it safely. If someone sold you a Cobra and told you it was 500HP and you expected it at the wheels, then you've got a bone to pick with them (or yourself depending on where the misunderstanding lies). you may also want to consider the difference between "shy of" and "plus"

You expect an engine builder to promise a RWHP number?

You really want to get into the dyno debate??? There's more mystery to that my friend. Dyno racing is another topic saved for face to face discussion.