383 Whiplash Cam Questions

[mcrivelli1898]

I have a 1968 Plymouth Fury with a completely totaled out back half that I've decided to pull the drive train from. I'm installing a freshly rebuilt 727 with a reverse manual valve body and 383 that has only 35k on it into my 1992 Dodge Pickup 2wd. I'm also installing the Hughes Whiplash cam. My concern is that on the Hughes website it states that the cam should be installed with big blocks with 8.5 to 1 compression or lower. From what I've read my 68 Plymouth Fury Commando 2 barrel would have came with 9.2 compression. Other upgrades I plan on running is a factory 4 barrel intake and Edelbrock 750. The gears I've got in my 8 3/4 are 2.92 but I do plan on swapping to a 3.55 or something similar to that size. My tire diameter in the rear is a 28" and the rough weight of my truck is 4000lbs. My question for the forums is what size stall converter to run and is the Whiplash cam to aggressive to run with my higher compression 383 to not be able to run 91 or lower. I do plan on going to set of aluminum cylinder heads in the future when I have the funds.

 

[CBODY67]

Regardless of the compression ratio, you WILL need to verify piston to valve clearance in the engine!

Reverse manual valve body. WHY??? That was originally a "race-only" item from the late '60s which "in the heat of battle" let the driver shift away from "N" rather than toward it, saving the engine. Modern electronics (and SlapStick shifters) can do a better job of that. Get the governor weights with the right "weight" for shift points at WOT, it might take more time to finesse that, but makes for a more pleasurable "put it in "D"" experience and still have the higher upshifts when needed.

With that much duration at .050, the 2.9 axle ratio is too high. As noted the 3.55 would work better with the taller tires.

Torque converter stall speed? A 2500rpm stall speed can really "stall" at 2000rpm or 2800rpm, depending upon the power in front of it. But that might be a good neighborhood to look in.

With the big difference in the exhaust duration from the intake duration, the cam is designe to work with stock heads and stock exhaust. Keeping the exhaust valve open longer to help compensate for flow deficiencies. PUTTING a good 2.50" dual exhaust system under the truck, too, would certainly help power output, betting a cleaner charge into the system due to better exhaust scavenging.

Just some thoughts,
CBODY67

 

[gyknot]

that's a huge lift difference from stock as well. the old street hemi grind cam I used to run was in the range of .474 lift and put my 4000# charger in the super low 14's.
My opinion is you will be unhappy with that cam in a street application.
With that said its your rig so you get to make the final decision.

 

[stubs300]

You should really be asking Hughes these questions, you'll get far better, more honest answers. No offence to the members here, but I'm sure someone will get their panties in a wad over this statement! Good Luck