Thread: help with choosing top end combo

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87 wrangler 350 sbc. Its currently has a lunati bracket master cam that is shot. It has stock heads holley street dominator dual plane intake, edelbrock 650 off-road thunder avs carb. turbo 350 trans shift kit and a 2500 B&m holeshot converter. My question is, should I just pull the cam and replace or go with a new topend combo? Its a trail/mud buggy and cruiser. Im looking for good torque throughout the power band maxing at 6000 rms or so, also of course horsepower. So maybe an Edelbrock top end kit? single plane or dual? This is my first build with my 14 year old son and it has been a great time for both of us.

A dual-plane, high-rise intake such as the Edelbrock Performer RPM or Weiand Stealth or Professional Products Typhoon will make more power and torque throughout the range than a single plane or low-rise dual-plane intake.

I like the results on my DynoSim of the Edelbrock 185cc runner aluminum heads on a 355 Chevy. Excellent heads for a reasonable price. Be careful though, I'm talking 185cc runners on the RPM heads, not the 170cc runners on the standard Performer heads. There seems to be a lot of confusion on the parts numbers, so call Edelbrock and tell them exactly what you want. There are also options for combustion chamber size and straight or angle plugs.

Pull your heads and make note of the piston deck height and piston crown configuration so you can figure your static compression ratio with whatever chamber size you will use. You need to know that before choosing a cam.

If you want, I can run DynoSims for you on different combinations. Some people say the software programs are unrealistic, but mine has shown to be within 2% and it's not the definitive number that's important anyway, it's the DIFFERENCE in numbers noted using different combinations of parts. It's the cheap way to find out what works without buying real dyno time and investing in a ton of parts.

Here's a simulation I ran for a fellow on another forum with a 355. His static compression is 10.3:1, which may be a bit high for what you want to do, but it still shows the validity of the Edelbrock 185cc heads....


Lots of cams you could use, but while I was in Edelbrock's site, I picked out the specs on the #7102 and plotted them in my DynoSim software. Looks like it works pretty well with the Edelbrock RPM heads, RPM intake, your 750 carb and 1 5/8" long-tube headers.....

RPM HP TQ
2000 140 367
2500 177 371
3000 228 399
3500 291 437
4000 350 460
4500 407 475
5000 450 473
5500 471 450
6000 478 418
6500 453 366

Use the head gaskets recommended by Edelbrock for these heads and set your squish to 0.035" to 0.045" to run pump gas without detonation.

Here's another, less agressive example that may suit your application better. This one uses less cam and less static compression ratio to make good power and excellent torque.
355, Edelbrock 185 heads, RPM intake, 1 5/8" long-tube headers, 9.5:1 static compression ratio, CompCams solid flat tappet cam, #12-222-4, 224/224, 0.499"/0.499", advanced 2 degrees and using 1.6 rockers on intake and exhaust. This simulation uses your 650 carb. You could make another 30 hp with more cam, but you'd give up this beautiful torque curve....(over 400 ft/lbs from 2700 to 5700)....(over 450 from 3700 to 4900)....
RPM HP TQ
2000 144 377
2500 182 382
3000 234 410
3500 295 442
4000 349 460
4500 393 460
5000 427 448
5500 435 415
6000 407 356
Comp recommends their #981 single spring with damper, 370 lbs/in rate and installed at 1.700", 105 lbs on seat.

Forgot to mention, Ive got Hedmen hedders part number 69648. They are the shorties they are the 1 1/2 inch primary. As this is a jeep wrangler with the sbc swap there isnt any room for much else inside the frame. I would have to go outside the frame with any other header. Basically ive got a lifted 4 inch go fast go cart. Oh also 4:11 gears with a electric locker.

If you're going to keep the 1 1/2" shorties, you may as well leave everything else alone too.

Guess I will keep puttering with it. Might have to go with fenderwell headers maybe. It makes that much of a difference from 1 1/2 to 1 5/8? Im running glass packs and they turn out just in front of the rear tires. sounded nice and the ladies liked the rumble.