Too Hot of CAM?

[jeepsr4ever]

have run the 8601 which is the profile you listed in a couple of stock compression 401's and had no problems towing actually towed really well, woke the motor up more so than most of the so called rv and towing cams out there. i also ran a 270H comp cam in my 360 powered rig with a 670 and that towed really well too, and in a 9.2:1 360 with a performer and the PAW version of that cam i had it in a 74 waggy with t-18 and liked it plently of snort in the 1500-5500rpm range, a little soft off from 1000-2000 but i was never in the 4 barrels at those rpms anyways so the gearing in the truck took care of the soft starts, soft start was just a slight tap of throttle as i was letting clutch out vs some of the other options where i could just let the clutch out and didnt really have to worry about keeping throttle up. I liked being able to down shift on a grade and pull 4000 rpm+ and still having power with a load and then being able to shift back into direct and keep chugging down the highway. most of my rigs have always cruised the highway with a trailer at 2500-3000 rpm at 65-70 mph+ and since that is my cruising rpm i have always liked the rpm buffer of still having 2k ov er that and still having power 1000 rpm under that.

That said i cannot help you with a rockers and bridges motor, all of my 360's, 390's and 401's that i have built if they are rockers and bridges i havent gone over 480 lift but with the stud motors all of my amcs that i have towed with and built have loved bigger cams for towing ect. 401's and 360s alike always get undercammd. also dont forget that nis a 114 lope sep cam its alot more behaved than you might think.

Dusty I just dont know about your builds out there. You seem to get power where it shouldnt be


Sure you aint polish boy?

[Dusty]

lol just a relative of yours.

shoot you have recommended 1/2 the cams for 1/2 of my builds and a few friends over the last few 5 years.

360-270h 9.2:1 ran good
360- 258EX 9.0:1 ran good
401 - Crower 284hdp? 512/525 lift 112 lobe 9.8:1 r4B combo ran great, towed was lots of fun
401- 8601 9:1 51cc heads on 8.5:1 pistons with the 8601 / performer - good. fun with a t-18
401 - howards .479 222dur@.050 292dur 114 lobe sep- 8.5:1 torker (dotn ask) and 600 - good
401 - Howards .479 cam - 10.2:1 and FI - so so think it may have been the fuel injection hindering performance
401 - 512 lift 274 dur 226@.050 112 lobe sep 10.2:1 with performer and 750 pretty fun mild idle great through to 5000/ 5500
401 - 9.6:1 270H Air gap and 770 so-so with a 670 and performer the same motor picked right up works great as a tower and mileage getter
390 - 10:1 R4B -700 - 276HDP Crower- OK performance done too soon rpm/power wise left a little to be desired on the mid upper and top end. in a 72 Wagoneer with T18 4.10s 32's
401 - 9.8:1 EX262h Comp - airgap and 750 pretty nice combo was snappier off the line with a performer but the airgap opened up mid and tops. tows pretty good in a J20 they said it was a 110 lobe sep but when it arrived the card said 112
360 - 10:1 343 pistons - EP20HYD Engle - Performer/700. Nice combo compression could have been a little lower but overall liked this combo it did really well with a TF727 and 3.92's in a J10. Had no problem on pump gas but towing it liked premium from time to time.

theres a few others in there
Oh yeah current cherokee is a 401 9.8:1 witht he 260h in it and 354 gears on 31's and a TH400 performer and 750 edelbrock tows great but she is done at 4000 rpm so kicking down to passing gear and trying to extract a few more rpms out of the motor with a trailer is not an option just staying in direct gear does pretty good on most hills loaded


i know its always been weird, the power does always seem to be there i can say the 280h in a 360 with a torquer and 800 was Way too much lol on 9.2:1. the PAW cam was close to the 270h in profile not the 8601.


On a recent 401 built i liked that 262EX from comp i think it would be pushing it for a low compression 360 but then again maybe not it might be a little large but may offer an interesting package.

[jeepsr4ever]

[Goose]

I would love to try a dual plane..I need to find one. I also need to find one for the 304 in the cj..(well ok I need to get off my half moons and finish the 360 for it..)

[82Waggy]

Found an interesting comparison of two 401 builds in this forum complete with cam cards and dyno sheets.

One is donwag's shown in the general chat section, and the other is jeep_man_401 shown in the general tech section.

donwag's uses a perfomer manifold, 670 Holley, 9:1 compression, and a Comp XE256H cam (110LSA with 42degrees overlap) with Edelbrock heads yielding 428ftlbs at 3400rpm, over 400ftlbs from 2000-4600rpm, and 348hp at 4800rpm.

jeep_man_401 uses a dual quad set up, 10.5:1 compression, a custom Crower 288/306 split duration cam (108LSA with gobs of overlap) with about 550 lift, and ported Indy heads yielding a little over 450ftlbs from 3000-5200 and 450hp at 5500rpm.

At 4800RPM where donwag's hp peaks, jeep_man makes an additional 25ftlbs torque and 50hp. At 3400 RPM where donwag's makes peak torque, the HP output of the two is about the same.

jeep_man_401 notes his truck is "b_tch" to drive below 30mph and comes to life around 2300rpm - but he built his to kill street rods.

Things that make you go "hmmmmm".

[82Waggy]

Interesting mix of engines you have there Dusty. Your assessments would seem to coincide with the combination of cams and compression ratios used. Do you have a favorite?


KJMac: Don't confuse "stock replacement" with "stock specifications". The 246HDP is designed to increase power in a stock compression engine with stock heads by closing the intake valve earlier to help build cylinder pressure, and optimizes valve lift to the flow characteristics of stock heads to increase port velocity. This is not a stock smog spec cam.

Bottom line is if you are not going to increase compression ratio from stock, stay away from long duration cams.

[Goose]

ok Waggy.. you get the eloquence award..You just said what I have been mumbling about.. the difference is you said it clearly!! good job.(and with the facts to back it up rather than the observations I used.)

[82Waggy]

Here is a general assessment of the effects of various cam characteristics:

More LSA = Widens power band, More peak power, Smoother idle with higher vac, Decreases overlap
Less LSA = Increases mid-range torque, Narrows power band, Faster reving, Increases overlap
More Duration = Moves power band up In RPM range - approx 500RPM/10 degree increase in duration, loss of low rpm torque due to later intake valve closing point can usually be gained back with increased compression
Less Duration = More Low RPM Torque
More Overlap = Better high RPM cylinder scavenging, Decreases vacuum, Rougher idle
Less Overlap = More low end response and torque, better fuel economy
Lift = Should be sized against ports for best velocity.

[82Waggy]

ok Waggy.. you get the eloquence award..You just said what I have been mumbling about.. the difference is you said it clearly!! good job.(and with the facts to back it up rather than the observations I used.)

Awe shucks Goose!

How 'bout you hook' em and I'll clean'em and fry'em!

[1980_Cj7]

Here's the specs on our Clevite cam. It's LINE NO. 2 on the following charts. Not to high jack this thread, but how do you experts think the engine will work if we go to 8.5 to 1 pistons and keep this cam. If you recall, we were having pinging problems, on top of all our other problems, when we had the Ross 9.8 to 1 forged pistons with this cam. Those pistons also were .017 down the hole rather than 0 like they should have been.

We're getting ready to put this thing back together and try again. One of the problems with this cam seemed to be the early intake closing coupled with the high compression pistons. I'm wondering if it might actually help the lower CR pistons though.