Lowbuck Shop/Race Truck Build

[maxracesoftware]

Nice work, showing 514 HP in a 29.52 Baro, not bad. Your porting was well spent money!

Mark ,
i entered 83.0% PerCent Drivetrain Efficiency Value ( 85.0%=Default value )
as you had Power Steering Pump + Alternator + Water Pump being all driven during DragStrip Runs
...it could be less Drivetrain Efficiency Value than 83.0 % ??? .... so HP could be in 520's to 530's Range
likewise , you did not Post if there was any Wind MPH .... that could increase Engine HP also if there was Wind + its Wind direction

[vortecpro]

There was a small cross wind maybe 7 MPH, turning the water pump, alt, power steering, through the mufflers, two piece drive shaft, with very heavy brakes. As you stated it made every bit of 537 HP corrected.

[Dave B]

My oldest brother has 72 truck. It's all fibreglass body. It has moly frame and cage .It would be cool to see what your engine could do at 900 lbs lighter vortec

[vortecpro]

My oldest brother has 72 truck. It's all fibreglass body. It has moly frame and cage .It would be cool to see what your engine could do at 900 lbs lighter vortec

I had the opportunity to buy a 86 short wide a NHRA stocker truck with all the right parts, aero space brakes, split mono leaf with a 12 bolt, cal traks, of course a one piece drive shaft, this could come in around 3600 pounds but more important no more drive train and rolling losses, but I think I need to just be happy wheres its at and enjoy it, I drive it every day the weather will let me. With out the exhaust and not turning everything on the front of the engine, iced intake, its a 11.20s truck, fast enough, and I have a few cars that need some attention.

[ClassicComp]

I had an 87 short bed silverado bright red very nice truck shoulda kept it.

[econo racer]

Mark of course its your money but I sure would have liked to see you race a set of the new aluminum camel humps against fairly stock vortecs. . Just upgraded valve springs etc.

[skinny z]

Mark_Jones_SBC291_cast_iron_Cylinder Heads Flow Test Data

Mark_Jones_SBC291_cast_iron_out_the_box_shape_May_21_2022.jpg
Mark_Jones_SBC291_cast_iron_after_Porting_Cyl4_Test_1_June_4_2022.jpg
Mark_Jones_SBC291_cast_iron_after_Porting_Cyl6_Test_1_June_4_2022.jpg

 
i had 1 #291 casting i Ported to duplicate how i Ported Mark's #291's
to make sure Mark's Heads had plenty of metal left for Street/Strip use,
so i went from 2.055/1.600 Valve Combo to 2.080 Intake Valve + more Port work
then i took it the 2.080 Porting all the way to breaking thru into Water Jacket bridge between Intake and Exhaust Valves
to be bery sure there was plenty metal there for Mark's 2.055 Port Job
here are Intake Bowl Templates :
VORTECPRO 291 SBC Heads Intake Bowl Templates.jpg
291_SBC_Meaux_Test_Head_Test_3_June_2_2022.jpg

Which heads are on the shop truck? These are 291's correct? (I believe I've answered my own question below).

Is there any indication of the intake port volume on the ported versions?

[skinny z]

I will be running a Vortec head on the 355, how would you cam this thing knowing I need to drive it, flat tappet cam?

A quick recap of my final build:

360 inch 2 bolt, 10.8 compression, 291 fuelie heads, 264/.528/108 solid flat tappet cam, air gap intake, 750 Holley DP, Moroso oil pan, MSD ignition, 6AL with a 85551 dist, my 327 ran a HEI.

I'm guessing from the most recent posts and those from Mr Meaux that they're the ported 291's.
I'm seeing peak CFM on the intake is around the mid 250's. Is that about right?
If you care to say, what lift have you targeted?
The reason I ask is that at first glance they're remarkably similar to the aftermarket Vortecs I have ready to go. Somewhat inspiring really given the results you get.

[maxracesoftware]

Mark_Jones_SBC291_cast_iron_out_the_box_shape_May_21_2022.jpg
Mark_Jones_SBC291_cast_iron_after_Porting_Cyl4_Test_1_June_4_2022.jpg
Mark_Jones_SBC291_cast_iron_after_Porting_Cyl6_Test_1_June_4_2022.jpg
Which heads are on the shop truck?
These are 291's correct?

Yes , they are the SBC #291 castings in those Pics
i Ported for Mark's Truck


I'm guessing from the most recent posts and those from Mr Meaux that they're the ported 291's.
I'm seeing peak CFM on the intake is around the mid 250's. Is that about right?
If you care to say, what lift have you targeted?
The reason I ask is that at first glance they're remarkably similar to the aftermarket Vortecs I have ready to go.
Somewhat inspiring really given the results you get.
Kevin

....from Mark :
360 CU IN
4.060X3.483
10.9 Compression
264/264/.528 @ the valve solid lifter flat tappet
1.5 Rocker
RPM air gap
750 Holley
37.5 timing

on a Land & Sea Dyno they made
536 Peak HP @ 6100 RPM

"If you care to say, what lift have you targeted?"
i targeted 0.550" Valve Lifts ( 0.200" -to- 0.550" Range )

my one #291 Head i already had in my Shop,
i Ported the Short Turn Curve a little more than Mark's #291's
to see Flow results = picked up into 260's Range at higher Lifts
and started to loose a little at Low-Lifts ,
so i left Mark's #291 Short Turn Curves alone ... i didn't max them out there !

Mark told me the #291's i Ported for him ,
Flow tested 8 to 10 CFM higher on his SF-600 Bench
so around 265's CFM on his Bench as received .

[skinny z]

I pulled my latest post down as I wanted to have a closer look at how the 291's compared to my RHS ProTorker.
I was going to point out how the .500" numbers compare and maybe have similar hopes for my 357 but on second glance your results below that are eye opening.
My were flowed on SF600 with a 4.03" fixture. 2.02"/1.60". No back cut. 170-175cc intake. 5 angle seats.
How much do you think that back cut help at lower lifts on those heads? One thing I see on that 291 is the work in the chamber. Something I posted about having to address.

RHS Pro Torker.jpg

[vortecpro]

I pulled my latest post down as I wanted to have a closer look at how the 291's compared to my RHS ProTorker.
I was going to point out how the .500" numbers compare and maybe have similar hopes for my 357 but on second glance your results below that are eye opening.
My were flowed on SF600 with a 4.03" fixture. 2.02"/1.60". No back cut. 170-175cc intake. 5 angle seats.
How much do you think that back cut help at lower lifts on those heads? One thing I see on that 291 is the work in the chamber. Something I posted about having to address.


RHS Pro Torker.jpg

Larry's porting was real good @
.200
.300
.400
.500

lift, but keep in mind he set the air speed for my combination, and it worked out excellent.

[vortecpro]

Mark of course its your money but I sure would have liked to see you race a set of the new aluminum camel humps against fairly stock vortecs. . Just upgraded valve springs etc.

I just wanted my 350 to look like my 327 did, production GM heads.

[vortecpro]

I will be running a Vortec head on the 355, how would you cam this thing knowing I need to drive it, flat tappet cam?

A quick recap of my final build:

360 inch 2 bolt, 10.8 compression, 291 fuelie heads, 264/.528/108 solid flat tappet cam, air gap intake, 750 Holley DP, Moroso oil pan, MSD ignition, 6AL with a 85551 dist, my 327 ran a HEI.

I'm guessing from the most recent posts and those from Mr Meaux that they're the ported 291's.
I'm seeing peak CFM on the intake is around the mid 250's. Is that about right?
If you care to say, what lift have you targeted?
The reason I ask is that at first glance they're remarkably similar to the aftermarket Vortecs I have ready to go. Somewhat inspiring really given the results you get.

I did see flow in the 250 range, but what I noticed was excellent .300-.400 .500 lift numbers.

[skinny z]

I did see flow in the 250 range, but what I noticed was excellent .300-.400 .500 lift numbers.

That's what caught my attention as well.

[maxracesoftware]

its great to work with someone like Mark Jones who has a ton of experience+knowledge
Mark makes my Cyl Head Porting look good !
He knows how to turn every Flow CFM into real HP to both show up on the Dyno and then on the DragStrip !

Likewise,
its also a pleasure and great to work with NHRA Stockers , SuperStockers, Comp Eliminator Racers/Engine Builders
they make a Head Porter look good !

Look at Mark's Forum signature !
"Racing a NA NHRA stocker should be mandatory before any posting."