Dynoed the 347 today

I've been asked a couple times recently at work and at the local cruise- in "how much power does it make?" So I too it to CPR and put it on the rollers just for giggles. Ended up with 392HP @ 6100 and 365 tq @4600.


Interestingly,a couple years ago,with a different cam,heads,and 650 carb,it made 406hp and 383tq on the same dyno and similar conditions.But was a solid 3 tenths slower in the quarter mile. Glad I took it to the track before I dynoed it LOL!

excellent!!

I've said it before and i'll say it again...yet another example of an engine making excellent power with canfields! If I were to ever get aftermarket heads, i'd look long and hard at canfields!

Is your custom cam a flat or roller?

Originally Posted by blkfrd

Is your custom cam a flat or roller?

mech street roller
230/244/113lsa

To me its the performance that is impressive..Lots of 400+ hp 347s around but not nearly as many in the 10s!

Would be fun to do the math according to the best pass on each combo and see what hp difference shows up. 3 tenths is a ton. Makes you think about the reverse split cams that throw up huge dyno numbers but don't accelerate down the track. Dyno hp and how an engine accelerates are not always the same thing. Acceleration is where it's at!

According to the calculator here your best pass of 10.92 at what I guesstimate to be a 3,200 lbs. race weight equals 431.56 rwhp and 509.25 fwhp. 11.22 (.3 slower) shows 397.86 rwhp and 469.48 fwhp at the same weight.

In the real world you picked up 34 rwhp and about 40 fwhp with the head and cam swap. From a very similar cross section head to another and a cam change that is a TON to pick up!

From this data I think a more true comparison of the two combos on the dyno would be to compare time to peak hp. This version of the engine would apparently show a significant advantage over the old one in this type of test. If you want Jay to design you another cam for big dyno hp and torque rather than acceleration I'm sure he could. LOL

NICE!

To get a better idea of how the engines compare, what was the MPH of the first combo? Do you know what the car weighs?

It's nice to see a stickshift out there kicking butt!

The car/suspension is working really well, running 10.8 at 121 with the stick!

Thanks and Good Luck!

Originally Posted by n2omike

NICE!
The car/suspension is working really well, running 10.8 at 121 with the stick!

Thanks and Good Luck!

I agree Mike. I believe the suspension in nothing super fancy either. Slapper bars and not Cal Tracks if I remember correctly. Likely also accelerating to peak power very quickly.

Frdnut-I'm definitely satisfied with the performance.And on that point,I had already made up my mind that I wouldn't be disappointed if it made 350hp and I wouldn't be overjoyed if it made 450hp.It is what it is.

Nate- I SWEAR to you,after the dyno guy made the first pull,the first words ou of his mouth were "man......that thing revs up quick"! LOL

Mike/Nate- I don't feel you could honestly do apples to apples comparision.My best pass thru the mufflers(as it was dynoed yesterday) is 11.04@120.54.
The old combo went 11.47@116.95. But that was the stock T5 granny shifting the stock t5,and it possibly could have gone faster with a 750 carb.It was also very cold that night(mid 40's).I feel like it was a a 11.30 car if I could have shifted it hard.
The car weighs ~3200.It ran the 10.92 with the exhaust off,so it was 50lbs lighter on that pass.

Originally Posted by 68fastang

Frdnut-I'm definitely satisfied with the performance.And on that point,I had already made up my mind that I wouldn't be disappointed if it made 350hp and I wouldn't be overjoyed if it made 450hp.It is what it is.

Nate- I SWEAR to you,after the dyno guy made the first pull,the first words ou of his mouth were "man......that thing revs up quick"! LOL

Mike/Nate- I don't feel you could honestly do apples to apples comparision.My best pass thru the mufflers(as it was dynoed yesterday) is 11.04@120.54.
The old combo went 11.47@116.95. But that was the stock T5 granny shifting the stock t5,and it possibly could have gone faster with a 750 carb.It was also very cold that night(mid 40's).I feel like it was a a 11.30 car if I could have shifted it hard.
The car weighs ~3200.It ran the 10.92 with the exhaust off,so it was 50lbs lighter on that pass.

So it ran 116.95 granny shifting in cold air. How much mph do you pick up power shifting over granny shifting with the new combo? Seems you still picked up a significant amount of mph with less dyno power at the rear wheels.