Seattle Active Power GT40 - A Father/Son build

slow but steady progress...some pics

Added the door bar to the Passenger side...notched the door. Next is to clean it up, and likely add some reinforcement


Door bar welded in.

I wanted some extra protection to prevent the front roll hoop from caving into the passenger compartment in a roll over...but still wanted a reasonably accessible entry. I ended with these hinged door bars; they are ~110 degrees from the front roll hoop, so in the event of a roll over, they'll remain in compression.

Pull the pin, and they fold down nicely.

My welds never look great...but I usually get good penetration, so they function. I upgraded from a ~12yr old Harbor Freight unit (cheapest they had) 2 years ago and it's been soooo nice.

Then I started to get some odd voids and splattering...finnaly found out that the pressure regulator was randomly dropping the sheild gas to 0; the pressure regulator was the last part of my HF unit. Time for a new one!

Seat Rails: I cut some thick L brackets, and weld those onto the side of the chassis. It pushes them as wide as possible, and lets the seat site low.


Welded into place

Tak'd into place w/ kart seat style mounting to the FG seat.

Final: got them apholstered locally, then I sealed them w/ Por15.
My good freind stopping by to lend a hand...driving the Lotus 7 kit that I build about 8 yrs ago.

Harrop's ITBs arrived...these things are beautiful!!

cover removed...and it better shows the real length of the runners.

mock up test fit...looks right at home!


Top it!

Backing plate test fitted...plan is to make an intake box around them; that way I can run a filter & MAF.

Headers arrived from Chris @ Active wonder they call these "Bundle of snakes"!! I was really worried it would take me the better part of the night to figure out how to install them, especially b/c clearances are so tight w/ the rear roll structure.

20 min later (inlcuding 10 min to find some random bolts that would work).


love the curves...
last set...more or less brings it up to date.

Installed a Corvetter oil pan, it reduced the pan height by ~2.5", so now the pan is ~1/4" below the chassis. once I get the tranny, I may raise it up to make it level.

While doing the oil pan, we also got a kit from Improved Racing, that included a crank scrapper & baffle. Since this is a 427 stroker w/ 4.125" crank, it needed some cutting to make it work. Main reason for going through route is that most ppl say once you pull more than 1G lateral, the LS3s are known to oil starve. So this kit adds a baffle to help.

Baffle installed

over the years I've learned there's no way my memory will ever be good I put all of my notes on blue tape around the areas that still need work. "No coolant", "no oil", "TQ Spark Plugs",...

Nice big oil cooler from Improved Racing. Includes a thermostat, temp switch to activate the fan,...and we'll add an accusump 3Q system.

Where have you been all my life?!?! I've been using cut off wheels to sheet metal for ever...sparks flying, metal dust,...then I found this. $40 from HF, and it cuts straight, quietly, and easy!

installing a footwell partition.

installing the throttle pedal mounts: using the OEM DBW pedal.

the OEM DBW pedal had a really long plastic pedal face that wouldn't I welded a small plate & bought an Aluminum pedal that looked similar to the Willwood Brake/Clutch pedal.

Pedals install. Still needs a few tweaks...but the spacing feels good, and heel-toe position is how I like it.
What sanctioning body will you be racing with and what class?
none at this's going to be an open track day car w/ some street use.

Here's a pic as I researched various ways to design a roll cage w/ the GT40's unique doors; Gave me pause...and with ~600HP, I know I'll want to stretch it's legs on the track, so it solid cage is good insurance.

Randy V

Lifetime Supporter
Please install a lot of padding on that cage if you plan on street driving it. We’ve lost people due to head impacts with cages.
Consider adding tubes between the front and rear hoops at the top corners (above windows) for your best on-track protection..
Please install a lot of padding on that cage if you plan on street driving it. We’ve lost people due to head impacts with cages.
Agreed. General principle for the roll cage was to design it such that you're more likely to hit your head on any other interior panel (or windshield). We'll also have padding on the key areas, and 6pt harnesses will be the sole seat belt, even on the street.

Consider adding tubes between the front and rear hoops at the top corners (above windows) for your best on-track protection..
We were going to do that, but with how far inboard the top of the door line is, the bars would have been too close to the driver/passenger head. I couldn't find any design that we liked...since the rear hoop already had rearward diagonal bars, we figured adding a similar bar (the pivoting bars) to the front hoop did effectively the same thing, and critically would prevent the front hoop top edges from caving into the interior in a roll over.