[Jeff Hamlin]

Originally Posted by Cammer-6

whats the numbers on that one Jeff?
Ive lost Brents contact info If someone can PM it to me thanks

It's a work in progress and this is what was shared thus far;
Getting close. Tested preliminarily at 7 pounds of boost. It was good for 289 HP and 315 lb-ft. Likely going to settle at 10 pounds. Goal is mid 330 hp, safely. Lot of effort for the outcome by todays standards but it should be fun.


Hey guys, this was originally a 1bbl head. There was an attempt to modify the head by a shop back east in 2009 or so. Extensive machine work was done to increase flow. They also installed oversized Chevy valves. But the valve stem length was wrong, they didn’t add dual springs and they threw in a custom Clifford cam (Rob Egbert now owns the cam) but they didn’t deck the cam tower to accommodate for the grind. It was a mess. When my dad passed the car along to me it probably had 30hp. The valves were burnt, the cylinder walls were marred up and it showed terrible wear for a car with under 40k miles.
When I got the car to Flagstaff in 2020 I tore down the motor and took the block to a local machine shop. Just an old shop in the back of an auto parts store. Nothing fancy. The block was zero decked and bored .30 over. They polished the crank, added ARP rod bolts and installed custom forged pistons from Ross Racing.
I sent the head to Jerry Woodland. It was one of the last he did before selling to Rob. He said he’d never seen anyone add oversized Chevy valves but he was able to make some modifications to the cam followers to accommodate the appropriate stem length. He also said that the actual machine work was very good so the head was salvageable. The rest of the appropriate modifications were made to the head, including dual valve spring and so on. The machine work and the modern head gasket increased the volume and pretty well offset the zero decked block, so my compression ratio sits at approximately 9.2:1.
I am running a 4bbl E cam. Again, nothing fancy or custom there. I also had a sprint damper refurbished and installed, however the engine hasn’t been dynoed with the sprint damper, yet. It peaked at 5200 rpm, with the 1bbl damper. HP and torque was just barely starting to taper off at that point so I don’t expect higher rpm to yield any additional power.
Funny thing, I spoke several times with Quinton at Primatech back in 2008/2009, trying to help my dad take a crack at modifying the motor back then. He gave good guidance and still had parts in stock. But we didn’t have the knowledge or resources. Primatech shut down shortly after. I still have the email chain. Those headers were certainly a missed opportunity, along with some other bits and pieces. The car has a Clifford intake and headers now.
More boost will produce more horsepower, no question. But will it handle 10 pounds? 🤞
Chris, if you have some insight as to what the limiting factor might be based on that conversation, I’m certainly curious.

[Cammer-6]

Many years back I sold a guy a new set of Clifford long tubes.
He installed them and a centrifugal supercharger with a blow thru carb
He says it made 400HP but i dont remember Tq numbers.
I think he said it was only 5 pounds of boost,as he built the bottom end stock.

Note to all. If you suspect boost may be in the future bullet proof the bottom end.

I would love to see the numbers if he cranked the boost up to 12 or 15.

PMD would stress test various engine combos by putting superchargers on them and increasing boost until it broke.

What a fun project!

[sprintbird]

I think the 400 hp number on 5lbs of boost is a bit optimistic. We have a couple guys running 7 to 15 on a stock-ish Sprint builds and they are short of 400 hp. A larger than stock cam turbo cam, some mild port work and 15 to 20 lbs and one would get there. The Sprints only make 180 to 185 hp NA.

[Cammer-6]

I found a reprint of an article Don Keefe did on the car.
This must have been sometime later that the article was written
because the figures all grew. It was up to 411HP and I think 385Tq
with 9 lbs boost.

[sprintbird]

Originally Posted by Cammer-6

I found a reprint of an article Don Keefe did on the car.
This must have been sometime later that the article was written
because the figures all grew. It was up to 411HP and I think 385Tq
with 9 lbs boost.

Makes for a good read, but I am still skeptical of the numbers based off of others builds and Dyno info available. Brent’s 301 was an all out, kitchen sink type build and he got 370 HP and close to the same Ft lbs NA. I find it very hard to believe 9 lbs of boost on a stock ish build netted 411 HP and 373 ft lbs. Probably closer to 300 HP.

[camerjeff]

Rob, it was probably just a very optimistic Dyno, HP Sells you know. There are a couple of chassis dyno's in my area that are known to show about 10-15% more HP & Torque than the others in the area. They seem to have longer waiting periods also. So if you just want to show how much HP your engine makes, and don't care about actual performance, pick the right Dyno!

Just my opinion, others may vary.

[Cammer-6]

Originally Posted by camerjeff

Rob, it was probably just a very optimistic Dyno, HP Sells you know. There are a couple of chassis dyno's in my area that are known to show about 10-15% more HP & Torque than the others in the area. They seem to have longer waiting periods also. So if you just want to show how much HP your engine makes, and don't care about actual performance, pick the right Dyno!

Just my opinion, others may vary.

hoping no ones questioning your #s with the stroker,that torque # is impressive

[sprintbird]

Gary, Jeff’s numbers are pretty accurate with his 301. This is due to the quarter mile times he was running and the story of how he walked away from the 289 Mustangs in the corners during a road race. A stock ish build would not be able to do that. I was only questioning the Powerdyne 250’s HP numbers from years back.

[Cammer-6]

Seems like we are comparing apples to oranges here.
A bored stroked motor has no resemblance to a boosted one.
I was first told 400hp with 5 pounds of boost.
Im guessing later the boost was increased to 9 and HP grew to 411.
It could be a somewhat optimistic dyno,but then again how do we know any of these dynos are spot on?
You are right that 1/4 mile MPH is a pretty good indicator. But thats subjective too.
So to get back on track lets see some more strokers

[Cammer-6]

any more stroker builds out there?