What gears in the back ?

 

i honestly do not know but they are stock gears for a 85 gmc 1/2 ton

 

"run like a turd" is a comparative term...sure it can smoke the tires, but a properly spec'd more conventional cam without all the Thumpr weirdness ground into it will be even more powerful, is what knowledgeable folks already know.

These Thumpr cams were designed to do one thing,,, to thump at idle and not lose too much power compared to cam designs already on the books....to please the domestic ricer boy/mullet head/"ricky racer" type's who think sound at idle means bad-*** power under the hood.

It's all just a marketing campaign from Comp Cams....you don't see any other cam manufacturer doing it, do you. Wasn't even thought of until "The Fast and the Furious" hit the theater and geeked out all the wanna-be's.

 

Smoking the tires means nothing. A combo smoke that some rather hard tires could bog and nearly die with the smallest slicks or a nice set of drag radials. You didn't really go into much detail about you combo. You could have one of the smaller thumper cams and an optional axle ratio and have accidently fell on a combo that runs ok but not the best you could do.

 

i ment smoke the tires at a red light hauling tail i drove the truck and its got a lot of low end power,we timed a 0-60 and its gots 0-60 in a 5.2 and it gets around town good and he drag raced it a couple times and beet quite a few people and it was only a quarter mile track but everyone tells me the mutha thumpr requires a 9.1 cr, but the motor only has a 8.5 and i also read that the gm crate 350 is even lower like 7.5 so how is this 9.1 cr mother thumpr cam running this good in this motor

 

We are just telling you,... you think it runs good, but a better cam pick would make it run even better.

I take the exact same engine out of this truck, chuck the Thumpr in the scrap can, and install a better matched grind, and I beat your time with the same truck. Thusly, the Thumpr would be "turd" by comparison even though it felt good to you.

 

your right a better cam would out match the thumpr but what i was asking how is this cam still running this good in this motor? cause the specs is 350 260hp 7.5cr 76cc smoggers but it has a 9.1cr cam in it and thats a huge jump on the cr so im thinking a cam like that would make the motor bog down so much that it wouldnt even hardly run but apparently its running extremely well for a oversized bark no bite cam,

 

Early intake valve closing and tight lobe separation, similar is done for low compression circle track crate engine rule cams for a lot of years now, Thumper just has long duration exhaust lobe for sound.

Same/similar technology, just in a new "marketing package"

 

thanks i think i understand now

 

If you ditch those heads for ANY 64cc head, you'll be worlds apart. I won't knock the Thumpr, it really wouldn't make a bad class-based circle track cam; problem is, there are better specific cams for less money. But you have it, and theres nothing wrong with liking the cruise-night idle, so lets maximize your combo. You need 64cc heads with 180-200cc runners. You need a recurved distributor. And, if you don't have it a Weiand Stealth/Performer RPM/Holley 300-36 high-rise, dual plane intake. Then you'd have a matched engine combo that would perform as well as that cam allows.

 

I once had a stock 350 from top to bottom with 882 heads and stock everything etc and ran a comp cam 292h and boy it sounded good and seem to run good in my old 86 s10 and it lit the tires up all night long and I thought it was a real power house but I knew nothing about engines and performance back in 1999 and have learned my lessons along the way about how everything needs to be matched and all needs to work together along with the transmission and the rear end etc. Bottom line it sounded good and felt like a lot of power but on a dyno I bet it would have floated the valves at 4000 rpm and the thing was a dog compared to what I have in it now. And yes I ran the Big mutha thumpr roller version of that cam and it was in there for just about two months and this was about 4 years ago and I have all things matched pretty well and I swapped out to my lunati voodoo roller 231/239 @50 535/550 lift which is smaller then the big mutha thumpr roller cam and yet my truck now runs the best it ever has and I also pull 19 mpg highway with a 650 double pumper carb. And yes I have a mullet lol but I am not your typical mullet back yard racer lol.

 

Ahh the 292H...the 90s version of the Thumpr LOL Every Joe Dirt in high school had one in his stock motor'd car with flowmasters, a 650 DP and the aircleaner lid flipped over...the "good" ol days LOL

 

I think the small thumpr cams would work well with a vortec head where the exhaust port is weak.If I build a cheapo vortec engine I see a use for the cams.
Or,if I had a fair set of heads and was building a 283 I would consider the thumpr and use 1.6:1 rockers on the intake side. Stupid names shouldnt sell the cams, I always think of the disney rabbit when I hear "Thumper",,,,,