Half-Breed

[Zachalanche]

Looking great man!

Thank you sir.

Looks great!

That is a very interesting 351 under the hood (notes on the hood).

I've got some extra SBF valve covers, maybe i'll cut them up and put them over the coils.

[Falcon64]

Zach,

I know when cortex first started he came in with his modular spindle. Most of the other parts he had were actual griggs parts or at least exact duplicates. I always kind of thought that he used griggs stuff except where he felt he wanted an updated part. Those always seemed like just a newer version of what griggs had. I am curious if you know anything about what if any relationship there is/was between the two.

Griggs and Cortex were almost-neighbors eithr side of me at Sonoma Raceway before Griggs moved 10 years ago. Each of their fabricators hung out together.
Griggs was elusive ....Cortex is the opposite, straight up and deep in the tech. Filip is a great guy.
P.S. i have a 64 Falcon Futura with chev power. Bought the body shell from a Cortex fabricator.

[214Chevy]

Close up of the hood vent. I was really on the fence about adding these, but I think they ended up looking pretty good.

Attachment 179656

I think the hood vents were a great addition. They add detail...

[Zachalanche]

I won't say the car is complete, but the rest of the things I have left to do won't be changing the overall appearance. I'm pretty happy with the color, it is red hot in the sun for sure.

[thumper877]

Looks great

[andrewb70]

Fantastic red. Looks very similar to the red on my GTO, especially with the black wheel centers and polished lips.

[ryeguy2006a]

Beautiful car man! Always great to see a project nearing the end of completion.

[Zachalanche]

I think the hood vents were a great addition. They add detail...

Looks great

Fantastic red. Looks very similar to the red on my GTO, especially with the black wheel centers and polished lips.

Beautiful car man! Always great to see a project nearing the end of completion.

Thanks guys.

[Zachalanche]

Finally the car is registered and insured. I took it for its first legitimate drive on real roads about a week ago. I must say this thing disappoints.....well maybe a better way to put it is that I haven't worked everything out yet.

The car cuts out pretty hard under full throttle. at first I thought it was a fuel supply issue. there was no problems like this when the car was on the dyno a few years back, so I wondered if it was related to fuel starvation under hard acceleration. the fuel cell has an internal baffle with trap doors so I don't think its unavailability of fuel, but I was suspicious of a kinked hose inside the tank so I replaced it with corrugated plastic line. Additionally The fuel pump was very very loud and this has since been corrected with a new Fuel filter/regulator.

After all that fun work the problem seems to be even worse which has me wondering if it is fuel related or something else.

On top of that the low speed drivability isn't great. not terrible but a little annoying. the engine rpm hangs around 2000 rpm for a long time when coming to a stop. and the the car is either bucking when you try to hold steady, or dead pedal when you try to accelerate (not completely dead, but not very responsive).

I read some things on other forums that mention the T56 Magnum has a 12 tooth reluctor wheel which doesn't play nice with the GMPP ECM which expects 40 teeth, and this can cause low speed drivability issues

Anyone her familiar with tuning GMPP stuff? and if so what is your tuning software of choice? I'm wanting to make some adjustments to the vss signal since my T56 reluctor ring has much fewer teeth than the ECM expects. this issue also doesn't allow my speedometer to calibrate due to low pulses per mile. Also, I'd like to look at the ignition map and see what the timing is at lower loads and speeds, and on crank. The starter has a hard time cranking when hot which has me wondering if the timing is too advanced during crank.

Any advice is appreciated.

[andrewb70]

I cleared my PMs...sorry about that.

Andrew

[Nova1970]

69-70 fastbacks are the best! Car looks awesome, I really like the stance!

[JRANGER]

Awesome ride, im building a 69 Mustang myself...Wont be anywhere near this nice but love the cars

[Zachalanche]

It's been a while since I have shown any updates on this. here's a couple recent pictures of the car.



I finally built a proper airbox. The plan is to eventually duct this airbox up to the hood scoop and obviously cut a hole in the hood making the scoop functional. I will need to fabricate some kind of plenum that sits under the hood scoop attached via the hood scoop bolts, then I will run flexible duct to the airbox. But for now, it's just pulling air from around the side of the radiator. the airbox could use some heat wrap. My engine compartment gets hot with this modern engine and its hot thermostat.



there's been a bunch of other random things I have been sorting out on the car, but I have been pretty busy the last couple of years and its hard to find time to even drive the car lately.

[Zachalanche]

After years of minimal use and being busy with life in general, I finally had an opportunity to enjoy the fruits of my labor at LS Fest West last weekend. The car performed great.....much better than its driver did. What a great time. I need to attend more events.

[MSTSFabbed]

The car looks great! I’ve enjoyed following your progress and have admired the car from afar for many years.

What ended up being the engine tune issue you were fighting?

[Zachalanche]

The car looks great! I’ve enjoyed following your progress and have admired the car from afar for many years.

What ended up being the engine tune issue you were fighting?

thanks.

The speed sensor would drop out occasionally which would cause low speed drivability issues and occasional stalling. this seemed to be related to the reluctor wheel being 12 tooth instead of 40. even though it was set to 12 teeth in the ECM, it seems like there was still issue with it. I set it to 40, and then compensated with the rear gear ratio in the tune so now the ECM thinks I have a 1.11:1 rear gear and everything runs great. At some point I am going to pull the tail shaft and put a 40 tooth wheel in the trans, but for now everything seems fine.

[Zachalanche]

A few more pics taken by Terry Lysak @tlysak


and a couple from theautobuilder.com

[Zachalanche]

suspicious oil

so I dropped the pan and noticed this coloration on the crankshaft:

So i checked the crankshaft play and found it to be around .014" which is a lot more than it should be. so I pulled the #3 cap:

looks like it wiped out the thrust bearing all the way down to the steel.....which means that the crank took on some wear as well:

So out came the engine:

once disconnected from the transmission there was .040" of crank play

looks like all the metal did some decent damage to a couple of the piston skirts so I'm looking at replacing the crank, pistons, and all bearings at minimum. But I don't have many good options for machine shops near where I live now (the one shop in town has been working ...or not working...on honing my block for the past 6 weeks.) so I'm not sure where to go from here. maybe there's a junkyard engine with a turbo in this car's future.

Pretty much a heart breaker. I'd like to think things would be better if I had never looked because the car was running great. but the crank was starting to eat through the #1 main support, and the rods were running almost all the way to one side of the piston, so I suspect catastrophic failure was a possibility in the near future.

[ryeguy2006a]

Huge bummer about that engine man... Been following your car for years and great to see those pictures. There are a few vendors out there that sell balanced rotating assemblies that you can just drop in. May want to look into something like that and what a great opportunity for a stroker.

[Zachalanche]

Huge bummer about that engine man... Been following your car for years and great to see those pictures. There are a few vendors out there that sell balanced rotating assemblies that you can just drop in. May want to look into something like that and what a great opportunity for a stroker.

This was a 418 stoker, so i'm looking at replacing with the same. I'd go bigger if I had the budget for sleeves, but....i don't. Sad thing about the 418 stroker (vs a 416) that I had not realized earlier on is that there is no room for repair. my bore is 4.080. the max bore for a stock LS3 block is 4.085, but no one makes a 4.085 piston.

Open to recommendations vendors if you have any. buying a complete rotating assembly currently appears to be the best route at the moment.

I picked my block up today since the machine shop never got to it. there are some minor scratches in a couple of the bores. Since this block is already at max bore, I can't really take much material out, so I'm just going to dingle-ball hone it and live with whatever scratches are left. The engine was running well and had no signs of blowby prior to tear down, so, despite not being perfect, the cylinders can't be that bad but I'll do some thorough measuring to confirm. from what I can tell, the cost to balance a rotating assembly is pretty similar to the cost of the rods. So, I might as well just buy the whole rotating assembly pre-balanced, and then sell my old rods for whatever I can get for them.

This engine also had a custom grind cam that I wasn't super impressed with. it wasn't terrible, but I wouldn't mind having the power be a little bit more peaky and maybe around 600 crank hp. this engine previously dyno'd at 459 wheel hp. I'm guessing that's a little shy of 600 crank. Given the displacement I would think that power would be achievable without going too wild with the camshaft.