[Jay S]

Did they use the Hydraulic roller version of the thumper cam or the HFT? Comp makes both a HFT and a HR with the same specs at .050”. May have to wait until Roadkill is aired to find out?

[Formulajones]

Squidward, I believe the duct tape drags have been going 4 or 5 years now in Tucson. I was going to attend last year but found out they put a 400 car cap on it and they were already full. I talked to David about it and he told me register early next year. Same track is what I was told.

Pretty cool dude who likes all kinds of different cars, not fixated on one make or model. Pretty rare in this hobby. He's someone I very easily get along with and enjoy talking to him.

[Jay S]

We have had some friends get to hang out with the Road Kill crew, they are a fun bunch of folks. I have a pretty similar car background with Freiburger, he and Duluth are entertaining to me. Finnigen is hilarious.

[Dragncar]

Originally Posted by Formulas

Is Motortrend back to producing new content?

You have to remember they are not really vested in best outcomes unless its their darling engines and they have sponsors tugging on their shirts and a crowd to entertain

440HP sounds weak for a 400 with good heads the thumper is a sound based offering

Not sure why anyone is not OK with his HP numbers.
Its a cast rod/forged piston 400 with a RPM, not bad IMO.
Remember when Edelbrock came out with their round port RPM heads and their version of the RAIV cam ? It made 422 HP I believe. or real close to it.
No one is making 500 HP with this guys cam and a 500 HP 400 engine is kinda rowdy anyway. Well, most of them.

[steve25]

That Edelbrock built from back then clearly shows what too much port area and not enough lift to acess the heads highest flow region does when nit enough CID and or rpm is not used.

[Stan Weiss]

Lets look at DF cam and a 60919 Note all numbers are at 0.050"

The huge difference is in overlap 28 to 11.5

Comp DF 107 LSA 107 ICl - IVO 10.5 IVC 44.5 EVO 51.5 EVC 17.5

60919 112 LSA 109 ICL - IVO 6.5 IVC 44.5 EVO 55 EVC 5

Stan

[Skip Fix]

FWIW my RAIV 400 had an UD HFT 288/296 231/239 @0.050 on a 108 that ran PB and A/C fine. 4000lb car ran mid 12s@108 with that cam through 3" mufflers 2.5' tailpipes exhaust in NMCA trim and tech.

[Steve C.]

For interest use the Advertised Duration Numbers and the Lobe Separation Angle here:

http://www.wallaceracing.com/overlap-calc.php

( For the purpose of this exercise presume the are both rated at the same tappet lift )

Comp Thumpr:

291
311
107

87 degree overlap

Crower 60919:

304
316
112

86 degree overlap

.

[Formulajones]

Originally Posted by Dragncar

Not sure why anyone is not OK with his HP numbers.
Its a cast rod/forged piston 400 with a RPM, not bad IMO.
Remember when Edelbrock came out with their round port RPM heads and their version of the RAIV cam ? It made 422 HP I believe. or real close to it.
No one is making 500 HP with this guys cam and a 500 HP 400 engine is kinda rowdy anyway. Well, most of them.

Agree. I didn't catch the hp number he made but if it's 440 HP from a 400 that's doing pretty well. You really have to push things to reach 500 with a little 400 and they would be beyond streetable by most people's standards in this forum which is why most build a 455. Even 500 HP with a 455 things have to be well thought out.

[Squidward]

Originally Posted by Dragncar

Not sure why anyone is not OK with his HP numbers.
Its a cast rod/forged piston 400 with a RPM, not bad IMO.
Remember when Edelbrock came out with their round port RPM heads and their version of the RAIV cam ? It made 422 HP I believe. or real close to it.
No one is making 500 HP with this guys cam and a 500 HP 400 engine is kinda rowdy anyway. Well, most of them.

440 hp is pretty gnarly in my book! But you guys know me, I play with 350's.

I'm easily pleased, tho. I got to where I was tired of playing constraint management, trying to make bulletproof the next weakest link.

[i82much]

i dunno about the cam but i replaced my quick fuel mech double pumper with an avs2 and second gear feels like first gear used to ... annular boosters are the titties!!

[steve25]

So your running the 800 cfm version of the AVS2?
Thumbs up to ya if that’s the case.!

[i82much]

Originally Posted by steve25

So your running the 800 cfm version of the AVS2?
Thumbs up to ya if that’s the case.!

yes that's the one ... dramatic difference in throttle response!

[Skip Fix]

Dyno numbers are like flow bench numbers- machine dependent! My RAIV 400 HO itnake 800 cfm Qjet 2" headers dynoed 385 on a very conservative dyno-through a muffler system. Wallace calculator shows 415-420 using 108 or 109. My pump gas 455 in the 78 now dynoed 525 on a different dyno also conservative at 3750 lbs and 124 Wallace pegs it at 587!
So 440 is not too bad for some Dport-even though aluminum-heads

[i82much]

I understand the Thumpr cams have stupid names and are marketed in a way that makes it seem like they are for guys who only care how their car sounds, not how it runs.

That being said, in the Pontiac world we have a lot of guys that want to go fast with engines that run as smooth as glass ... so you see the Jim Hand type approach has influenced a lot of the thinking around here, wide lobe sep, long stroke, etc.

I dunno exactly what the takeaway is from the dyno numbers here and I understand dyno numbers can be misleading ... but I do kind of sense that maybe if I guy doesn't want a tractor motor then tightening up the lobe sep with a shorter stroke can get you some pretty good power numbers.

Just my impression.

[Jay S]

I think the Thumper cams are overall designed best for Chevy engines where the piston has more acceleration off of top dead center at lower RPMs. Generally it seems like the shorter the rod to stroke ratio, the better they work. The longer the connecting rod, the worse they work, the worst engines for those thumper cams seem to be a small bore engine using long rods. Just my observation, but on a lot of those applications is appears there is not enough piston speed coming off of top dead center for the RPMs too utilize the extra overlap. The result is a bunch of the fuel and air charge gets blown out the exhaust. That 235/247 thumper is not a big cam, at least not in terms of useable RPMs. In a 400 it only has the same top end power band of a 60243 Crower (228,[email protected] 112LSA) which to me is pretty small yet. I would guess the 60243 could pretty much match the road kill (HFT)thumper cam for toque and on that same engine beat it by 20 HP up top. If you swapped and put that thumper cam in a 400 SBC with stock length rods I think the results would totally flip. I did a 110LSA Bullet HFT 235,243 @.050” with .566” lift in a 10:1 406, had VPro lifters. That could bury a 60243 and was still very tame. The thumpers can work in Pontiacs, but they generally don’t work great. Seem like they work much better in 455s than 400s.

Road kill cars have a lot of parts in them just because it is available and in stock. Their goal is just to get the engine running and on the road, not necessarily to get the most out of it. It is still fun. I have noticed the thumper cams are almost always on stock.

[Stan Weiss]

Does anyone know if there was ever a video posted of this engine on the dyno?

STan

[Jim Moshier]

Apparently, it was Dyno at Steve Dulchege's Dyno at his house, and it is in the last episode of RK Garage that has not aired yet. Not sure if his Dyno was checked for accuracy. Big numbers look better than accuracy.

[Stan Weiss]

Originally Posted by Jim Moshier

Apparently, it was Dyno at Steve Dulchege's Dyno at his house, and it is in the last episode of RK Garage that has not aired yet. Not sure if his Dyno was checked for accuracy. Big numbers look better than accuracy.

Steve, is able to check if the dyno is reading correctly himself if he wants to.

Stan

[Skip Fix]

My old machinist had a very conservative older dyno. Nearby machine shop had a "generous dyno". That shop owner died in a racing accident so he took it over-a Superflow dyno. It took him a week to get to calibrated to read correctly by Superflow instructions