Machinehead Powersports

Machinehead Powersports I have been doing this type of work for 32 years, and I'm not done yet! Complete instalation/custom fab/design facility. We can install your parts/our parts.

Race car cages and complete custom chassis fabrication. Custom built engines for Drag, Road Race, Muscle Car, Hot Rod, Off Road and Marine. Custom disk brake kits or ordinary kits can be installed and tested. Complete Original H-O racing suspension systems can be installed. We can also locate a special car for you, through our locating network, and have it delivered and modified to your specifications.

67' GTO received a set of 12.88" 6 piston front and 12.19" 4 piston rear brakes from Wilwood. Rears were pretty much a b...
07/27/2026

67' GTO received a set of 12.88" 6 piston front and 12.19" 4 piston rear brakes from Wilwood. Rears were pretty much a breeze with mild shiming. Fronts required drilling and taping the spindle to accept the 5/8-18 upper adapter bolt. Pedal is firm with a manual 7/8" Wilwood master. Test drive soon to map out the front to rear bias.

439 BBC is coming along. Autotech pistons are assigned to their bores. My final piston to wall clearances below. Assigne...
07/16/2026

439 BBC is coming along. Autotech pistons are assigned to their bores. My final piston to wall clearances below. Assigned all my crankshaft bearings. Had to mix-n-match #5 main with a Std. bearing to get it to snug up. Rods are next, then send the rotating assembly out for balance. BTW the head is on and torqued with a gasket to simulate my running skirt clearance.

449 FE Dyno spark plug. The spark plug is a very good indicator as to what is really going on inside the combustion cham...
07/11/2026

449 FE Dyno spark plug. The spark plug is a very good indicator as to what is really going on inside the combustion chamber. A sight glass really. No matter what the AFR gauge says or what the timing reads, the spark plug tells you what way to go and the resultant HP quantifies your decision.

07/11/2026

Ran the 67' Fastback on the dyno
Great results with 430rwhp @ 5800
And 485lb/ft at 4100.
This is a 449 inch FE In an original GT390 car. Really stoked on this build considering the hurdles! I had previously dialed in the carburetor and timing curve. So all there was left to do was a spark plug check and verify timing at 33 degrees. Parasitic drivetrain losses on this combo are 80-90hp. 510hp crank HP. The low curb weight and big power make this thing a real blast to drive. Specs are on my page below.

Dyno charts from the 467 GTO. Some plug reads.
07/11/2026

Dyno charts from the 467 GTO. Some plug reads.

07/11/2026

Had a surprising day on the dyno. The 467 inch 67' GTO put down some really good numbers.
509RWHP and 530lb/ft. Over 500 lb/ft from 3200 to 5200. Peak power came in at 5800rpm. Peak TQ at 4200. Made a big swing on the AFR and it didnt change much. Also pulled 1 degree of timing for a total of 33 degrees. Parasidic drivetrain loss on this combo are 70-85hp. Flywheel estimates are about 600hp. There is detailed build specs on my page below.

Here comes another one!439 inch Big Block Chevy.
06/11/2026

Here comes another one!
439 inch Big Block Chevy.

04/01/2026

The GTO

1967 GTO delivery a few weeks back. Customer loves it. Had to do some unusual carburetor tuning. Transfer slot fuel feed...
03/31/2026

1967 GTO delivery a few weeks back. Customer loves it. Had to do some unusual carburetor tuning. Transfer slot fuel feed was out in left field at 0.117". Restricted it down to 0.076" to get rid of the extreme rich cruise mixture or 10.4:1 AFR. went from 82 square jetted out of the box to 78 primary and 93 secondary coupled with a 10.5 power valve and its spot on. 14.1 cruise (e10 fuel) 13.2 idle and 11.2 WOT (again e10 fuel!) Fuel curve is t**s. Went to a 0.037 squirter also from 0.028. Thanks to Otto Tharp for the old H-O Racing headers!

Delivered back home. 1966 Ford Fairlane GTA 390FE. Runs great took it for a short putt around the property. Replaced pus...
03/31/2026

Delivered back home. 1966 Ford Fairlane GTA 390FE. Runs great took it for a short putt around the property. Replaced pushrods and completed break in procedure. Installed factory console and shifter. Replaced heater core.

Address

4950 Bell Springs Road
Dripping Springs, TX
78620

Opening Hours

Monday 8am - 5pm
Tuesday 8am - 5pm
Wednesday 8am - 5pm
Thursday 8am - 5pm
Friday 8am - 5pm
Saturday 9am - 5pm
Sunday 9am - 5pm

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