[HWYSTR455]

Originally Posted by chuckies76ta

You'll still do really good with the 1-7/8" headers. These exhaust systems have to be all custom installed so they fit properly. I had my Son help me with ours as he's a welder. I did both cars at the time with all 3" mandrel and full 3" Trans am tips. Came out beautiful. There was lots of fabricating to get the tips installed with 3" though. Wish you were closer as I'd love to help with exhaust. It's a fun project in my opinion. Work of art when done.

I wish you were closer too! Heheh! I usually get it really close and loosely install the U clamps, then take it to a shop to be welded up. It's been working really good that way for years, many systems, but it would be quicker if I had a welder/MIG/TIG.

On the GTO, the 3" splitters don't look right to me, so I will do 2.5 tailpipes and tips. Same with the 71 T/A, the hockey stick 3" tips just don't look right. Also, it has a 9", and the larger axle tubes make it near impossible to run 3" tailpipes. It's a 463 stroker, 315cfm heads, so think it will be much less of a restriction.


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[Steve C.]

Dave Bisschop's custom 'Road Paver' uses Comp High Lift Magnum lobes.

Lobes 3115 and 3116 and typically ordered with a "B" lobe suffix code.

Used with a Pontiac cam journal size the rated duration is 306/314
Duration at .050" is 246/252
Duration at .200" is 164/169
Lobe lift is .4000" on both lobes.
It is ground with both a 112 and a 114 lobe separation with typically 4 degrees advance.

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[Steve C.]

Something a bit bigger than the Dave Bisschop Road Paver.....

He has done a 535 using Edelbrock 345cfm heads at 10.75:1 compression and a hydraulic roller cam in the 250's / 260's with a 114 lobe separation and lift in the upper .600s.

With a highly modified Victor intake, both runner and plenium work, 1-inch HVH Super Sucker and a 1050 Pro Systems Dominator it made 718 hp at 6100 rpm and 663 ft.lbs. at 4900 rpm.

With a 4150 Victor intake and a modified HP950 it made 694 hp at 6200 rpm and 660 ft.lbs. at 4900 rpm.


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[Formulajones]

Originally Posted by HWYSTR455

I mentioned that 571 build above, curious, what's the bore & stroke on that?

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It's a 4.750 stroke and 4.350 bore

It made those numbers with a Victor intake and 2 inch super sucker with a 4150 950 HP on top. Oddly dynod with a dominator and it only made 6 more HP but the average torque dropped over the small carb so it was decided to keep the 4150 on it for more air cleaner choices.
It was also dynod with the 2" chassis headers he runs on the car and bischoff had a short 3" exhaust setup attached to it.

Typically dyno operators run a dyno header on there similar to sprint car headers which will inflate the numbers a bit more

[65 Lamnas]

I ran Doug's 1-7/8" primary headers, 3-1/2" to the x-crossover, and 3" for the remainder including full tails. I had 2 different induction systems dynoed for it....a Q-jet/ported HO and a Holley 950/1000/TorkerII setup. The Q-jet/HO combo made 605 peak HP...and the torque peak wasn't much different from the 667, but can't remember the exact number. I was going to try a Northwind which was new at the time, but life happened and never got to it. Another thing worth mentioning was that I added a vacuum pump due to the long stroke, which solved my "oil out the dipstick under hard acceleration" issue. Never took it to the dragstrip, but ran it with a vericom on a county road one cool fall day. It showed a 10.90et at 124MPH with me and a friend in it at the time. The thing was a barge at 4080lbs...

[HWYSTR455]

Originally Posted by Steve C.

Something a bit bigger than the Dave Bisschop Road Paver.....

He has done a 535 using Edelbrock 345cfm heads at 10.75:1 compression and a hydraulic roller cam in the 250's / 260's with a 114 lobe separation and lift in the upper .600s.

With a highly modified Victor intake, both runner and plenium work, 1-inch HVH Super Sucker and a 1050 Pro Systems Dominator it made 718 hp at 6100 rpm and 663 ft.lbs. at 4900 rpm.

With a 4150 Victor intake and a modified HP950 it made 694 hp at 6200 rpm and 660 ft.lbs. at 4900 rpm.


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Hm, would have expected to see more, but could be more accurate/conservative dyno.

24hp is a good jump, but there too, would have expected more. Maybe both showed more average HP?


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[HWYSTR455]

Originally Posted by Formulajones

It's a 4.750 stroke and 4.350 bore

It made those numbers with a Victor intake and 2 inch super sucker with a 4150 950 HP on top. Oddly dynod with a dominator and it only made 6 more HP but the average torque dropped over the small carb so it was decided to keep the 4150 on it for more air cleaner choices.
It was also dynod with the 2" chassis headers he runs on the car and bischoff had a short 3" exhaust setup attached to it.

Typically dyno operators run a dyno header on there similar to sprint car headers which will inflate the numbers a bit more

That's what I was thinking, 4.75 stroke. What was the lead time on that crank?


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[HWYSTR455]

Originally Posted by 65 Lamnas

I ran Doug's 1-7/8" primary headers, 3-1/2" to the x-crossover, and 3" for the remainder including full tails. I had 2 different induction systems dynoed for it....a Q-jet/ported HO and a Holley 950/1000/TorkerII setup. The Q-jet/HO combo made 605 peak HP...and the torque peak wasn't much different from the 667, but can't remember the exact number. I was going to try a Northwind which was new at the time, but life happened and never got to it. Another thing worth mentioning was that I added a vacuum pump due to the long stroke, which solved my "oil out the dipstick under hard acceleration" issue. Never took it to the dragstrip, but ran it with a vericom on a county road one cool fall day. It showed a 10.90et at 124MPH with me and a friend in it at the time. The thing was a barge at 4080lbs...

With my sound & heat deadening, serp setup, stereo and other equip, I suspect I'm closer to 4300lbs, but same thing as dyno numbers, I kind of don't care.

I think your intake(s) may be holding that combo back some.


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[HWYSTR455]

I'm running a Tomahawk baffled valley pan with an OE type PCV, plumbed into the base of the carb pad on the Victor, and I see at most a slight 'misting' of oil at most.

You sure your dipstick isn't just rattling out? Did you see evidence of oil in the intake before the vacuum pump?



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[65 Lamnas]

Originally Posted by HWYSTR455

.....I think your intake(s) may be holding that combo back some.


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No argument there. Undoubtedly left some on the table....but I was already paving roads two stripes at a time, and a more appropriate intake was not going to improve paving efficiency....so....

[65 Lamnas]

Originally Posted by HWYSTR455

I'm running a Tomahawk baffled valley pan with an OE type PCV, plumbed into the base of the carb pad on the Victor, and I see at most a slight 'misting' of oil at most.

You sure your dipstick isn't just rattling out? Did you see evidence of oil in the intake before the vacuum pump?

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I ran a "massaged" 68-72 pan, with PCV in factory location and vacuum source to carb baseplate. Dave speculated that it was simply the "whirlwind created in the crankcase due to the long stroke". I "think" it was built with a crank scraper, but it's been many moons ago and I'm old and absent-minded.

[Skip Fix]

Originally Posted by Formulajones

It's a 4.750 stroke and 4.350 bore

It made those numbers with a Victor intake and 2 inch super sucker with a 4150 950 HP on top. Oddly dynod with a dominator and it only made 6 more HP but the average torque dropped over the small carb so it was decided to keep the 4150 on it for more air cleaner choices.
It was also dynod with the 2" chassis headers he runs on the car and bischoff had a short 3" exhaust setup attached to it.

Typically dyno operators run a dyno header on there similar to sprint car headers which will inflate the numbers a bit more

On my 500 we dynoed it with my Demon 850 that has been great on every engine as well as a 2" Dominator adapter and an 8896 and no difference in HP and a little down on the low end.

[Formulajones]

Originally Posted by HWYSTR455

That's what I was thinking, 4.75 stroke. What was the lead time on that crank?


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At the time it wasn't much lead time at all. I want to say he had it in a couple weeks but that was going on 8 years ago now. Today, not sure, everything seems to have a massive lead time now.

It's a big reason I scrapped the stroker build I was doing and just bought a blueprint 598. They were in stock, dynod and ready to ship.

[Formulajones]

Originally Posted by Skip Fix

On my 500 we dynoed it with my Demon 850 that has been great on every engine as well as a 2" Dominator adapter and an 8896 and no difference in HP and a little down on the low end.

Ah so we aren't the only one that experienced that. I thought for sure the dominator would shine on a 571 and it was Tony's go to dyno carb that he's tuned and tweaked for years on many combos but it just didn't impress on Dad's engine for what ever reason. In fact Tony was shocked at how well the little 950 HP ran on it. I think that carb actually only flowed around 830 cfm on the bench.

[Skip Fix]

I still have the Dominator and have had Jeff(Shaker 455) tweak it back to a 2 circuit so it may go back on at some time on a dedicated 4500 manifold. Probably not until we start seeing better 60 fts anyway.

We also tried a removable sleeve Demon 4150 with the largest sleeves so more than the 850 size-not much there either. All of those were on a Victor 4150 manifold. Cam Comp .406 High torq lobes on a 112 LS 108 IC. 1.65 Crower Ss shaft system

[Steve C.]

Here in this example only about 15 HP difference between a 4150 carb and a 1050 Dominator carb....

I have a old Brad Urban model 4779 Holley 750 Double Pumper carburetor . It has his Stage 3 modification and without the use of a 850 Base Plate he rated it at 926cfm. It has the choke tower removed. On my previous 4.125 stroke 450 CID combo with a 4150 Victor intake that carburetor and a 1/2-inch open spacer supported 684.1 hp at 7000 rpm. On the same engine with a 1050 Victor intake and a 8896HP Dominator carburetor and 1" cloverleaf spacer it made 699.9 hp at 6900 rpm. Both intakes were properly port matched to the cylinder heads, and both with some minor runner blending and plenum clean up.


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[Dragncar]

BBCs have giant heads, Our best is not even middle of the road with them. You can make just about any HP you want with one AND cheaper.
BUT !!!! they are not cool and never will be.
I would rather fight with a Pontiac and one hand tied behind my back than run one.

[Formulajones]

Originally Posted by Dragncar

BBCs have giant heads, Our best is not even middle of the road with them. You can make just about any HP you want with one AND cheaper.
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That's why they are still hugely popular in a wide range of motorsports and probably always will be. Aftermarket support is huge and big hp is just bolt on parts away and relatively inexpensive compared to some brands. Then of course there is the ability to accept large cranks in stock blocks as well as make really stupid power without the need for an aftermarket piece.

[Scott Stoneburg]

Originally Posted by HWYSTR455

I wish you were closer too! Heheh! I usually get it really close and loosely install the U clamps, then take it to a shop to be welded up. It's been working really good that way for years, many systems, but it would be quicker if I had a welder/MIG/TIG.

On the GTO, the 3" splitters don't look right to me, so I will do 2.5 tailpipes and tips. Same with the 71 T/A, the hockey stick 3" tips just don't look right. Also, it has a 9", and the larger axle tubes make it near impossible to run 3" tailpipes. It's a 463 stroker, 315cfm heads, so think it will be much less of a restriction.


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I was able to snake 3.5" over the rear on my 1st gen Firebirds. 9" rear with the shocks moved inside the frame rails, the gas tank has been narrowed though. It's tight,but do-able..I'm not saying you need 3.5", I had 3" on it before I built these.

[HWYSTR455]

Wow, that's impressive! I've only tried off the shelf bent tailpipes, and the 'loop' is too close together. I actually even tried denting the loop too, no-go.

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