But the ATI Super Damper claims to be a 7.5" OD
The factory Harmonic claims to be 7.5" OD

Do you feel there might be a discrepancy? I'm at work - otherwise now... I'd measure and inform the crowd here.

My reasoning behind buying a new stock length belt, as well.

 

Update from last night:

#2 Solved/Fixed
#3 Solved/Fixed

This leaves #1

 

If you have an electric water pump and F body accessories, here is another option to consider -- short belt mod. Ditch the passenger side tensioner, get a jegs LS adjustable alternator mount, wrap the crank pulley, PS, Alt, and the Driver side idler. Crank it tight with the adjustable mount. Voila! Room for a vacuum pump!

 

That is actually something I've had in mind, especially considering I would like to run a vacuum pump. Little update:

Belt 790K6 - 79" - Stock length - even during easy driving, will hang half-way off and ultimately slip off.
Belt 780K6 - 78" - 1" shorter - during easy driving, will not come off. During WoT run to 7000 RPM, will slip half-way off.

The 78" built is at the *very limit* of what the tensioner can adjust to. While the 780K6 is safe for daily driving, it's not safe for the occasional "pull" on the highway. I'm also going to presume, the added tension will cut belt life in half or more?
None of the pulleys/accessories have any wobble to them, all are flush.. Pulleys are all dry and free of any oil/fluids.

My next item will be replacing the piece of sh*t "duralast" "stock tensioner" with the AC Delco. You might be asking why I ever bothered with the Duralast... well, it was sitting around and I put it on.
I'm hoping the switch to AC Delco for a true OEM tensioner will fix it...but I just don't see how, I'll try it anyway.

Thanks,
Andy

Edit:

And to be absolutely fair here, I've actually *never* had any kind of issue ever, with any Duralast part, personally. So yes, I trusted it, even if it was a foolish thing to do. Ultimately, at this moment, I'm still not sure if that's the culprit anyway.

 

I have some crazy experiences with that tensioner. I had to put one one a few years back. About a year into it, I drove to LA, and it broke just outside palm springs. Like broke in half, lost the belt, and only reason I noticed was the steering - because I had EWP, it never overheated, which was cool. With no other options and stuck in LA and the only one in stock was at autozone, I installed the duralast part.

A year later - driving to LA AGAIN - it broke in half AGAIN. And this time I was lucky I noticed it, because I had converted to manual steering. Only indicator was battery voltage. This time I was like "F" this tensioner and tried like hell to wedge a short belt on without an adjuster, and I couldn't make it work. So i got a THIRD duralast tensioner. After installing it, I sat in the parking lot revving, and I noticed, when I rev, the tensioner moved about an inch. So I babied it the rest of the trip, ordered a jegs alternator mount, and never looked back.

In general I have no issues with duralast stuff, and I'm not trying to trash them or anything, but I kind of reached a point after a few of those that I was just done with the tensioner at all. There should be some incremental performance improvement to less belt mass and fewer pulleys to turn, so not a bad mod in the end.

 

Oh wow, that's exactly the kind of feed back I could hope for...That actually gives me hope. I'll look for an AC Delco one in stock and run with it, and see how it goes.

Thanks Darth!

 

Update:

1) Fixed - Thanks everyone especially Darth for the feedback on the duralast part. The AC Delco fixed all my belt hop issues, using even a stock length belt. F*** yea. Because I enjoy overkill reliability, I ordered an manual/adjustable comp cams tensioner.
2) Fixed - This was indeed the high pressure hose that went bad.
3) Fixed - Obvious (new spark plug wire)

New list:

1) Calling Dyno shop - I haven't done this yet, mostly because I was trying to get the belt hop sorted... the other half of the reason, is because I'm a lazy bastard. I hate dyno shops (I know, I'm weird) - but I would rather tune things myself on the road first. Which...I've done. So now.. I have nothing left to do but call them, and set up an appointment.

Thanks everyone - and I hope to have updates soon...preferably a dyno sheet,
Andy

 

Thanks for the update.
Let us know the results and show the dyno sheet.
Hopefully all goes well.

 

I got a Katech manual tensioner, they're a nice piece.

 

So my OEM-like AC Delco ultimately failed as well. It was doing great, but they just can't handle the 6900rpm/500tq or whatever it is that it doesn't like.
I'm really glad that as "go to solution after this fails" I purchased a manual tensioner (Katech/Comp Cams) and I have that in there now.
So yeah PSA, ditch the auto tensioner... something that everyone else on this board already knows, but hey whatever.

Update on the Dyno Tune:

The best place in Utah for LSx Dyno Tuning is backed up until late July, I have a date scheduled...

Thanks,
Andy

 

Update:

Just drove up to Premier Complete Autocare in Utah.

Although it sounds like a generic name, they have a good reputation. A couple of friends recommended them. So far, the car is just chilling outside their shop.

Waiting to hear it turn on and get on the dyno. I'm just waiting/working (my job) remotely while I sit and wait (patiently).

I'll be reviewing their place and my experience here. As well as posting a Dyno sheet.

Stay tuned.

Thanks,
Andy

 

Keeping in mind:
LS 427
Low compression ~9.9:1
PRC Cathedrals 247cc
238/254

Target AFR (Not seen on sheet): 12.6
WHP: 512
WTQ: 471

 

Really, for low compression AND a baby cam (AS ls7'S go), that's pretty good. When you gonna hook up the blower?

 

Thanks Darth for the feedback.

I'm in the research stages of mounting the blower. Right now, I know I want to go with a Griffin Radiator, and a Lincoln Mark VIII Fan (4100 or so CFM of air)
There is an older thread some where about people who moved their Radiators to fit an F1X.

Long story short: 2 to 3 months from now *at most*

I still have to do all the supporting fuel work.

 

Damn that's pretty good without a blower and such low compression.
When you install that blower your top end will be insane.
Looks like that 238/254 116 LSA +3 cam is as good as I was expecting it to be.
If your comp was 2 points higher I reckon you would have made another 30rwhp.
Hope you are happy so far.
I am expecting to get mine back this week but I'm still waiting for those damn ignition leads to turn up.

 

So far I'm very happy with it. Thanks again for taking the time to give a good recommendation, and thanks to everyone who chimed in.
My concerns have now shifted to other things - such as my overall configurations ability to handle the inevitable 800whp.

1) Best case scenario, I realize my quench at most, is around .026 - rough estimation based upon calculations - probably not good for boost?
2) ARP Head Bolts - not Head studs - I realize almost everyone in that power range in the 800's+ are using head studs - i wonder what the likelihood is that I'll push water...
3) 4 bolt main - coupled with #2, I assume the worst, as I always do - Pushing water at those power levels

So.. maybe I'm being overly cautious, but I am curious if those 3 factors combined will blow **** up.
I know people have made more power on completely stock internals and stock everything aside from ARP Rod bolts, but...how long did they last I wonder.

Things I have helping me:

1) Lower compression

Thanks,
Andy

 

You're worry over nothing. Your tuner matters >>> 1-3 above.

 

Your input really does help me feel better. That's good to know, and very true... I guess sometimes all I need is a second opinion haha.
I trust my new tuner, so I should be good...

 

Update:

Quick run down of the mounting:

Everything is bolted on. 3 bar map, upgraded fuel, fan/shroud combo, etc. Plenty of threads about how people mount this, but I kept my stock radiator, and removed the condenser for now, simply because the Condenser line was pissing me off, so I told it to **** off. I fabricated a shield for the impeller as I have no filter - the shield is pretty "all-encompassing" - however I'm sure it's taking away a lot of performance, the impeller is facing the radiator. A nice little bi-product of this is... I cut out a section of my radiator shroud to make room for the head unit, which leads to lowered engine temps because the impeller is sucking air through/around the radiator. So when I step on it, my engine actually stays around the same temp or actually drops a few degrees. I found this pretty hilarious. Again, probably killing performance, but it's what I've got going on right now.

Some perfomance tid-bits:

I hit 120kPA @ 5200 RPM - so about 2lbs of boost on the F1X - Because I'm tuning it right now, I don't want to nail it. Slowly working my way up the RPM's. This is about what I would expect from running a 14 deg. overlap cam, low compression, and the largest pully they offer (5.25"). I'll crank it to 6800rpm later on once I get my AFR down correctly - for now, I've set the timing in peak areas down very low. 9 degrees at WOT on highest g/cyl, and 13 just above and to the side.. The rest is normal. Long story short, I'm predicting to make about 7lbs of boost up at the very top. SUPER Modest/conservative, I'm sure my engine is pissed about how over-built it is and what a ***** I am.

Regardless, **** starts to get squirrely real fast on my 315 Toyo Proxy's out back. 1st gear is essentially useless the moment I hit around 3500rpm, but then again, that was a problem even before the F1x, but probably more so around 4800rpm.

Second gear starts to spin badly past 4000rpm. I'm extremely happy with the cam selection (thanks Bort) as this is exactly what I wanted. It is very friendly down low and I'm sure the real monster will continue to sleep until after 5800RPM's or so.

I'll keep everyone updated on what I end up tuning this thing to.

Thanks for reading, and I welcome any thoughts/feedback,
Andy

P.S

Haven't even called the dyno tuner yet. Another $500 I'll spend another day.

 

Andy!
Been waiting to see how you are going with your project.
Glad to see you are extremely happy with the camshaft I specified for you.
I am surprised at 3500rpm the engine is already going crazy. Haha
That camshaft will pull to 6800rpm without an issue.
I hope you have a stout valvetrain and everything matches. (Unlike my engine if you have read my thread)
Once you get the boost working properly you should have a very flat power and torque curve from 3500rpm+
The pro chargers just keep pulling in the top end.