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I remember back in 2002 or so, Marv Jorgenson told me that most 502's
dynoed at about 340-350 rwhp on the BH.

ZZ4's were about 230-250 rwhp.

When my 502 was stock, it ran about 343 rwhp.

Ric, to answer your question, the blower was a Vortech - V7-ysi on the trike.

Vortech V-7 YSi-Trim Supercharger

View larger image
Performance Specs
Max Speed: 65000 RPM
Max Boost: 30 PSI
Max Flow: 1600 CFM
Max Power: 1200 HP
Peak Efficiency: 78%
Performance specs apply to units equipped with heavy duty gearcase.

Dimensions
Discharge OD: 3"
Inlet OD: 4"
Discharge ID: 2.64"
Inducer Diameter:

Bill,

I was highly suspicious because of what I had seen and heard at the track but then when I bought my '57 Chevy trike with the 502 and nitrous, it just seemed to under perform. I ended up going to two quality speed shops in Ft. Myers, one of which had been modifying new Corvette's for me for years. They told me the same about the crate 502 and we substantiated it with my buying some dyno time from them and trying to tweak it. We got pretty into the nitty gritty paying particular attention to AFR's which seemed to make a pretty substantial tuning difference. We never saw more the 350 RWHP.

I then met some guys at the track who were doing some sensational stuff with Mustangs. Most applications were turbo but they also were running a few supercharged cars. Their 1/8th mile times were incredible. They were really cool young guys and in spite of being die hard Ford guys, were intrigued with the trike and helped me tweak the nitrous and carb set up. They too had a quality DynaJet dyno and we were seeing pretty consistent 330's and 340's as far as RWHP. My motor by the way was A-1 so that wasn't the cause of the lower than advertised numbers.

Geezer's observations at the time substantiated my findings and concerns. We discussed it occasionally and it was what it was. The only other variable I'll offer which seems to be consistent....all dynos are not created equal. You can find numerous dynos and tuners who will for whatever reason greatly embelish those numbers.

I also felt the numbers were accurate simply by the times I was running. Mid 300 hp with perhaps 150 shot of nitrous was supported by my high 6's at the track. Traction was solid using 325 Hoosiers (street/strip). If that motor was making anything close to 500 hp and then my spraying it, there would have beenlower to mid 6's second times as I started spraying with 200 h nitrous shots.

I think Ron can also substantiate much of this relative to the track as his 502 BH trike nnever ran better than 7 second times. With a true 500+ hp and Powerglide tranny, the numbers cam down to mid 6's. None of the 502 BH trikes see those kind of times.


Nothing to be ashamed about BTW with mid 300's hp at the wheel. The 502 is still a torque monster and has awesome attitude and "wow" appeal. I wouldn't stop loving it or feel the need to defend it in your shoes.

Elliot

El,
No doubt that horsepower to the rear wheels has always been a disappointment on Boss Hoss bikes and trikes. I have found that it is very hard to extrapolate accurate crank horsepower of an engine based on quarter mile/eighth mile E.T. or rear wheel dyno, though. There are just too many variables.

So, what is your belief regarding ZZ502 crank horsepower right out of the crate? Just how much is GM (Government Motors) fudging their HP numbers???

Bill

Bill,

At first, my disappointment with the numbers was based on my doing some of those Daytona style dyno runs on those portable trailer dynos and on the bike instead of the trike. I always figured it was Nesco's fault because that was the only thing between GM's claim and the numbers I was seeing. When I did it on the trike on a Dyno I had confidence in and had a reputation as being accurate, I didn't know what to think. Was the T350 responsible for that kind of power loss? Percentage wise, it was huge yet the T350 enjoyed a pretty good reputation.

That's when I started doubting GM's 502/502 claim but I have no data other than what I've written about earlier to prove or disprove it. You can read one article that says GM is full of shit and another that says they're understating the numbers. I suspect it's no different than bathroom scales except with me, the opposite strategy. I like the ones that make me weigh LESS!

Regardless of what the 502 is actually producing, it's almost a non issue in our world as you know what happens when you put the available power to that single tire now. Whether 340, 450, or 502 HP, it's a cool ass motor and has plenty of balls.

Going a step further, Some of the forums I occasionally read with the Nova, Chevy S-10, and Chevelle folks, love the crate 502 as the benchmark power plant to build on. Nothing needed for the massive bottom ends of those motors but when you start to play with heads, cam, intake and fuel, you can make a monster out of them and there's no hurting them. Claims of 700+ HP circulate those forums regularly. I really admired Tommy's bike listening to it and hot rodding with him in Oklahoma last year. It was nasty...

Your "Gov't Motors" remark really hits home. I've been kicking myself pretty good having bought a new Silverado right at the time GM pandered tax money from Yobama. Then they still lose money, whine, and aren't selling anything. During the same time, Ford borrows no money, is breaking sales records, and I liked the F350 I sold better than the 2500HD Chevy I bought. Crap...

Els