. Did you ever get this re-cammed and sorted out? The ***** Thumpr cam prolly wanted to work at 3500 - 7500 RPMs... the 280H at 3,000 - 7,000 RPMs... plus, your 9.5 compression ratio is too low to work well with either of those big cams...

. The 268H is prolly the biggest to consider for your purposes... 252 to 268 somewhere's... also, need headers and dual exhaust to really let the new engine do its thing... the stock 360" single exhaust system will make the 390" feel like a weak 360... fix the engine/exhaust and then see if the gearing needs changing...

 

Jeeeeez just saw the date.


Love my 270HR Comp.
Makes 500 ft lbs. with stock D2 heads and a 4.125 stroke and bore.
9 1/2 to one pistons.
Hauls *** with 3.50s and 33s.

 

To the OP, any updates to your puller? I am interested in anything related to sled pulling with an FE. I agree with redroad, 3.50/3.70 gears are too high with the C6. What is your class weight? I pull in the 6500 stock gas class with 4.88 gears, C6 and 31" tires. Sometimes when the track is short and a good clay base it still is a struggle. After 3 years of pulling I am still amazed at how hard that sled pulls!


Nick

 

Just a couple of comments. It sounds like a really nice engine. Also, when going down in cam size, the springs you have for the bigger cam should be OK. Also, reduced cam duration may increase tendency to ping or detonate. With 9.5 cr, even with aluminum heads, this is a consideration. The 280 cam sounds pretty good to me. A 260'ish cam may be a little small for that compression ratio.

 

I'll check it out in my engine sim, but so far I've not been impressed by the mother thumper in SBF or SBC. They're good for noise, but not impressive otherwise. In a SBC you get the noise of a decent beast, but the power of a mismatched set up. My bud had a Air Gap and a 750 on a 327, thing made like 250hp. Just didn't have much power. The previous build with the same engine, tune port injection and a cam that would work in that still came out to around 275hp, idled like stock and didn't sound impressive, but it would run.

They got 422hp out of one, they can't be all bad, but there are certainly better cams out there.

 

. This guy had two different threads on here for the same problem... but never followed through on the advice given or results... doesn't post here anymore...

 

I have a nineteen seventy one f one hundred with a three ninety. Four barrel carburetor elder block intake, headers and dual exhaust. I am.Looking for a lopey sound And also be a dependable driver. It is not my everyday ride but I do not want something too radical.