I’m building a replacement engine for my ’97 1-ton crewcab dually. It’ll be dropped a few inches, but not much because it’ll be my hauler and tow rig as well. I’m basically trying to build a hot street engine with a small cam so if I ever wreck/sell the truck, I can pull the engine and it’ll be a cam swap away from being a great street hotrod engine. It has a 4L80E with 4.10 gears and a factory posi in the 14bolt full floating rearend. Could some of you Desktop Dyno gurus run this thru and see what it says? I expect torque to be higher than horsepower, can’t really see it revving to 6K with the cam. Let me know if you need any additional info.

Gen 6 454 block, torque plate honed at 4.255
New flat top Wiseco forged pistons, -4.5cc dome volume, custom for this bore
Forged GM crankshaft
Forged Scat ProComp rods
-702 closed chamber castings, 2.19/1.88 valves, bowls blended and cleaned up, chambers reworked on Serdi
Static compression 9.25:1,
Crane Cams hydraulic roller, P/N 168721, 214/220, .563/.554 @ .050
L29 454 truck intake, gasket matched and cleaned up

I welcome any advice/criticism/recommendations for changes as well!

EDIT: Almost forgot, 1 3/4" primary full length headers


Thanks in advance for your help!!!

I'm betting it'll make you smile...when you stick your foot in it.

anything significant about the L29 intake?

I'm snowed under right now and don't have time to mess with a pic, if you haven't seen one, this explanation isn't going to make much sense.
It's the stock big block "Vortec" intake. It has a big throttle body but a convoluted path to the heads. The incoming air has to make a huge loop, a pair of cylinders at a time at first, then splitting into individual runners about halfway across the top of the intake. There's a choke where the runners split, but I'm taking most of that out. You'd think this would hurt torque, but the runners are very long anyway if you consider they split into pairs about 16 - 18" before they get to the intake gasket. The ports are about the same size as a smallblock intake port where they split, so I'm taking about 5" of that out until the runner cross section is no smaller than the intake face of the head. It can't help but be a torque pig but it's rev-restrictive in stock form. There's another big choke where the intake bolts onto the heads but it's very easy to remove and enlarge the port since the intake is a clamshell type which gives very easy access to almost all of the runner area once the halves are separated. I actually have a brand new stock intake and an old one that I'm doing all the porting on. I can swap the top part in about 15 minutes and do back-to-back testing. All the work I'm doing on it is to increase top end charge - the truck is a 4x4, so with LO gearing, lack of torque isn't one of my concerns, I want to see if I can get it to pull hard to 5500 - 6000.
I'm sorry that doesn't make any more sense than it does, but it's difficult to explain and makes perfect sense if you have one in your hands.

I dug out my old original copy of DYNO 2000. Not sure if I did everything correctly. I used the air flow numbers for the worked 702's on Stan Weiss' database, 9.25 CR, I entered the number for your cam (seat to seat) from the crane website. Am I correct in that it is a 107 ICL and a 112 LSA ?

Also, assumed small tube headers (did not figure the ratio to determine if they would be considered large/small tube for this engine), and used 770cfm on a dual plane.

Let me know if you dont think it looks right.

rpm hp tq
2000 194 509
2500 247 518
3000 294 515
3500 342 513
4000 374 490
4500 377 440
5000 352 370
5500 314 299
6000 257 225
6500 196 158

If anyone has any input on using DYNO 2000 please chime in.

Some people call a curve like this a "tow engine"....I personally would love something like this in a highway geared STREET car.

Same everything....next larger cam...

CRANE CAM 168731
rpm hp tq
2000 169 443
2500 224 471
3000 270 473
3500 322 483
4000 370 486
4500 403 470
5000 413 434
5500 393 375
6000 256 311
6500 307 248

Kevin ,What's the induction flow rate you used?
And post the .300 lifts you used.

Mike, You'll have to re-phrase your question for me.

#1 not sure on the induction flow rate ? The carb is set at 770 cfm @ 1.5 inHg
#2 Do you mean the cfm @ 0.300 lift? (I/E was 179/115 with a 29" H2O pressure drop)

Kevin
#1 - thought this was FI ? So looking for the CFM of the throttle body.
#2 - good enough.

Ahhh...I gotcha now.

Not sure what would be correct for TB intake....the closest thing listed is "tuned port injection" which, all else unchanged, appears to boost the torque slightly and dampen the HP curve.

No,not the intake but the throttle body.
GM's used a variety of sizes and I don't know what came with an L29.

Seems to be an 80mm and EA shows about 1100 CFM.

Right, I couldnt tell you either on that.

Busted Knuckles would have to chime in for corrections.

Heres the reasons that I'm asking.
I've used DD2000 and it had issues with roller cams.
Bruce corrected some of that in DD2003 before he sold to ProRacing:
http://www.proracingsim.com/
Anyway with the 770cfm and stock 702's (your flow #'s) ,I get 456hp@5500/534tq@3500.
Now if I go to the 1100cfm of the TB and use modified 702's I get 470hp@5500/540tq@3500.

No problem Mike. I like your numbers better anyway !

Sounds like I need a software upgrade...

I'm out of town for a weekend with a beautiful woman.
I'll get the info you guys need when I get back.
Thanks all the same!!!

Download comp cams new cam selection tool - put in your specs and you have your own desktop dyno, for free.