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what first gear ratio is it? unless it's a 3.09 first gear tranny, I'd stick with one of the two comps, probably the smaller one.



I have no idea what the 1st gear is? whatever came in a slant 833 od 84 truck?

I looked it up somewhere on the net and it does look like a 3:09 1st gear

The cams i have are a
268 h could be an xe not sure but i think it might be

Second one is a 274 xe which looks like it is discontinued?

both appear to be on a 110 center line

Is there much difference? I know the old 108 dc shaft detonated badly with a 9.7 :1 motor ( I measured it before and after the rebuild )



268H is 268/268, 218/218@.050, .454" lift, 110 LSA, 48 deg overlap

XE274 is 274/286, 230/236@.050 .488/.491 lift, 110LSA 60 degrees overlap.

268H will make more torque, XE274 will make more HP. using comp's camquest6 software, assuming 7.8 compression, 600 CFM carb, dual plane intake, headers, and flow data taken from hughes website for '576 heads w/2.02's, it's predicting:

308HP@4500 & 387 TQ@2500

switching to an XE274 yields

331HP@5000 & 382 TQ@4000,

one thing to remember is your gear spread and RPM drop. A833 OD's are 3.09, 1.67, 1, so your 1-2 shift will drop RPM's 46%, 2-3 will drop RPM's 40%. ideally you want to shift at or slightly above your HP peak, and drop to near your torque peak.

I think the numbers & RPM's are off on the comp simulation, I'd wager the 268H will peak HP at ~5200 & TQ at ~3000, and the XE274 more like 5800-5900 and 4000-4500. with the wide gear spread and the heavy weight of the truck I think I'd still look at the 268H, and shift ~5700 RPM (will recover at ~3100 & 3400...with the XE I'd say you'd probably need to shift near 7k to get to a decent shift recovery point for the cam (7k shift would recover at 3800 & 4200) and by then I'd wager you'd be too far past your HP peak that you wouldn't be gaining anything. if you had a closer ratio 4 speed with deeper gears, or an automatic with a loose converter, I'd go with the XE.

1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)