The GT-4 Manta came with TWM sidedraft intake manifolds. These are arguably the best flowing as-cast intakes for an Opel engine, but there's always room for improvement.

I decided it would be beneficial to at least port-match the intakes to the head. Port-match may be a misnomer, as I actually made the intake manifold a little smaller than the head to avoid creating reversion. By the same token, the opening of the intakes where the carburetors bolt on are a bit larger than the carbs themselves.

The completed intake manifold, fully ported and painted.

Here's the oil pump housing of the timing cover. I sprayed it with a dry film lubricant, which needs to be cured in an oven at 300 degrees F for one hour. Don't know how well it will work, but it should at least help to fill some of the voids in the gear housing. I got the dry film lubricant from Techline Coatings. They sell do-it-yourself performance engine and exhaust coatings.
http://www.techlinecoatings.com/

Kinda out of character for me, but I had the underdrive pulleys for the GT-4 racing engine chrome plated at my friend's chrome shop.
I'm usually not one for chrome, but I have to admit it looks pretty awesome, and as my friend owed me a favor or two, the price was right ($0.00).

Got some other junk done to the GT-4 Manta. Kinda scattered (like myself), haven't concentrated on any one specific area lately, but at least I'm getting stuff done. Hope to have the body repainted next week sometime, and the fuel system replumbed. Still need to dig out that last few parts to assemble the engine, but the block and head are 100% complete sub-assemblies

Thought some of you might like to see the solution for a milled head. Besides correcting the cam timing via an adjustable cam gear, the chain tension should be taken into account. I added a custom lash-cap to the hydraulic chain tensioner to keep the tension on the timing chain. It's 1/8" thick and has a hole for oiling too.

To keep the tensioner in place, I TIG-welded the lash cap in two places. Tried to keep the heat down so as to not overheat the spring inside the tensioner, just a couple of tack-welds.

Jumping around a bit, I had removed the front upper valance from the Manta....it was full of bondo and weighed about 16 lbs., plus it didn't even look like it was the right shape at all. It obviously was tweaked at one time in the car's past.
One of the list members, Duane Foley, had kindly loaned me a NOS Opel sheet metal upper valance. It was new, but was riddled with small dents from all the years. I never intended to use the actual sheet metal valance, but rather to use it to make a mold for fiberglass parts. I figure a fiberglass part will weigh around 3 lbs or so, at least at the thickness I will make it.

The problem is, the finished part is only as good as the mold, which is only as good as the original part the mold is taken from. So I had to sand it to bare metal, and hammer all the dents as best as I could, and then do the typical bondo work to 'cherry' it out. After that, I used a high-fill urethane primer to fill the remainder of the imperfections. I block-sanded the primer with wet 220, 400, and 600 grit paper, then sprayed two coats of black lacquer over it. Finally, that was scuffed smooth with 1200 grit wet/dry paper, and 4 coats of urethane clear were sprayed over that. Now I have to play the waiting game, and let it cure for a week or so. If I rush it, the fiberglass resin will lift the paint from the part, and I'll have to start over again.

Once it's cured, I'll wetsand with 1500 grit paper and buff the surface. Then the mold will be built. It will have to be a 4-piece bolt-together mold to allow for the edges/returns to be removed from the mold.
Note the typical dents. Not severe, but they'd look like crap if left alone.
Little patches of bondo everywhere.....
It looks worse than it is, most of the filler was sanded away
The finished part after priming and painting. Even in black, it looks great now

NOTE: NEED MORE PICS HERE

Latest project: dash panel for the racecar.
I had to make this pattern over three times. It had to clear the rollcage dash bar, clear the steering column, and most importantly.....be visible behind the steering wheel and the driver's hands (doh! This aspect caught me out initially).
Here's the final pattern for the dash panel, simply made from corrugated cardboard

The cardboard pattern, an aluminum pattern for use as a 'permanent' template should I need to make another part, and the final part made from .063" aluminum with two bends to help aim the gauges at the driver.

The new aluminum dash, showing the steering wheel as the determining factor for gauge placement. Tha dash panel will be secured via Dzus fasteners for quick access to wiring.
Gauges include (from left to right): water temp, oil pressure, oil temp, tachometer, fuel level, voltmeter, exhaust gas temp, clock (can't race if you're late to the grid!), and an hourmeter for establishing service intervals (no odometer!). There are also warning lights for water temp (220 degrees), oil pressure (30 psi), and oil temp (270 degrees). At top central I will add an Armtech rev limiter/shift light. The dash will be painted flat black to reduce glare

A few more pics from tonight's projects. Got the steering wheel spacer in finally, this moves the wheel another 2" closer to the driver. I had to custom-make an adapter to go from the 6-bolt Momo wheel to the 3-bolt spacer and quick-release hub.