Brain fart question 914-6 Options

[mb911]

So I am helping a member put brakes on his 914-6 conversion and then put carbs on it. He previously has a poor working sniper setup. It ran ok prior according to him. Then they switched to a 123 dizzy and removed the MSD ignition and then took to a tuner prior to my part. It ran much worse once the 123/MSD removal. The owner decided he was done with his sniper setup and asked me to put carbs on. I did that and for the life of me we can’t get it to run right. Starts pretty easy and idles decent. When I go to throttle up by hand on the cross bar it doesn’t want to accept all the fuel and shoots quite a bit back up through the horns. My suspicion is a major timing issue as in 180 off. The carbs are new and setup up by Dave Chenny so very confident in them. Seeing as the car is 1.5 hours away each visit I am looking for a bit coaching here. What else should I be looking at? The engine is a fresh 2.7 not built by me with about 1000 miles on it.

Help with some ideas please.

[technicalninja]

I'd "baseline" that first.
I've not actually rebuilt a 911 engine yet.
I've been inside to repair but have limited experience with the H6.
What I've seen (especially the cam drive) is NOT what I'd consider "beginner friendly".

Lots of spots to screw up on.

I'd want some idea as to what the compression ratio was and cam specs (if possible).

At this point-if the comp/cam combo looked funny-I'd post on this forum for your opinions!

Then I'd start with cold compression and leak down. Safer for spark plug threads IMO.
If problems weren't revealed, go for a hot run and recheck both tests.
During the first run session I'd be messing with the timing to see what improved my problem.

I once solved a weird problem on a friend's Legends race car with staggered valve adjustments.

Cold comp 180 across 4, hot 195-200.
leak downs 92% cold 95% hot across board, did not vary.

Run great for 2 heats, so-so for 2 more, then worsening trash for the rest of the night...

I had Marty recheck both tests after the car went to shit.
Leak down 94-96% across
Compression 185 160 140 115...

The air-cooled 4 cyl motorcycle engine is installed sideways and the rear cylinders ran hotter and retained heat between races more than the front.

Loosening valve adjustment .001" per cylinder fixed it right up...
Turned a front runner cold-dead last hot vehicle into an "all night" monster.

Cost nothing but a little time and I never touched the car.
Did that one over the phone...

Marty was stoked, he'd tried a bunch of ignition and carb BS while chasing this issue.

When I have a confusing one, especially if it's been recently "rebuilt" doing full basic engine baseline cold then hot is where I'll start.