AFR 225 71cc big bores. As for the LSA, there are two schools on that one...both Speed Inc & EPP recommended 114-115*, but LPE likes the 118-121*. I already tried the 118 of the GT2-3 and know what it did, so I figured I'd see what the 114 did for it. As Last Call said, we got very near equal numbers seeing 2 lbs less boost so the 114 cam/LTs is definitely more efficient than the 118 cam/shorties.

Yup, ASP makes a complete 8-rib conversion kit for the GM trucks (with 8" crank, alt, water pump, & idler pulleys--I did get my SC drive pulley elsewhere because try as I might, I could not get the specs for the shaft diameter out of Magnuson at the time), but don't know about the TBSS.

I do have the Alkycontrol kit & a NW 90mm TB (cable type, like oem). You're right about the IATs...they are about as high as is tolerable. And according to Rick, driving the SC harder will likely provide further diminishing returns. I will have to log and see what the timing is doing, but I suspect that you are correct at 12-13* total.

Rick is really impressed with the TVS at this point, and would love to see me upgrade to make some BIG numbers. I want to see what I can squeeze from the 122hh, and will definitely mill my AFRs or swap heads to see where that takes me. So far, I don't think I have spent any money on parts that cannot be utilized if I do decide to upgrade to a TVS (a 2300 if I do) later.

As mentioned above, although I would prefer not to have to do it, the next step will probably be a 4L80E swap.

 

What are your power or ET goals?

 

Well, as outlined in the very first post, when I built the 383 engine & swapped from the mp112 to 122hh, I was targeting 600/600 and breaking into the 11s. When we came up with 507/517, obviously I was extremely disappointed and felt that something was terribly amiss. Through extensive tweaking on the tune, Rick was able to find another 46 rwhp & 68 rwtq which put me at the numbers I had prior to the cam/LTs swap.

Since the tuning was not able to bring out the 600/600 goal, nor the sub-12 ET (12.70 @ 106) I decided to start the part swapping process to see what improvements could be found. And you see the results of the first attempt, a net loss of 6hp/9tq and 2 lbs boost.

Honestly, I have about given up the idea of the sub-12 sec ET without resorting to n2o, but my goal to surpass the 600/600 mark with the 122hh is still alive and kicking. I will mill the heads next and see what that brings.

 

I know you don't want to hear this but it is what I hear from everyone it isn't all about the power to get the time you want. Maybe back to the 3.90 or 4.10 gear with lighter shorter tires?

 

You are right about that. I have a set of 4.10 gears for the new 14-bolt on the workbench (and want to install a Tru-Trac with them when they do go in), along with a set of mounted M&H 275/50R17 (28" tall) and unmounted MT 275/40R17 (26" tall) DRs in the garage. I never thought that I would consider the 275/40 DRs, but I'm liking the "highway" 3.42 gear ratio so much that I may give those a try. If that doesn't give me much then the 4.10 gears with the 28" 275/50 DRs might be a decent alternative.

 

I don't think going to a smaller pulley to shoot for more boost is going to help much other than give you more dyno number, heat, and the ability to say you make X.X#'s of boost. I wouldn't even go any smaller than you have right now. What you're going to end up with is a quicker 1/8 mile time with a lazy mph in the big end. Doing the 80E swap may slow you down some from power loss and the lazy first gear. The advantage though would be that you could lock the converter in second and third gear to take full advantage of the torque you're making without having to spin the blower rpm as high. This is where Krambo made his best times. He didn't run an 80E, but he did find that just keeping the rpm down (lower shift points and locking the converter) and squeezing every big of power it made down low kept the IAT's lower during the run and netted him a better time. I am curious though if you have considered switching to E85. It's not very expensive, runs much cooler, and is 105 octane. On top of that with your's being a Tahoe/Yukon body there are ton's of them in the scrap yards with wiring harness's, fuel lines, alcahol sensors, etc, to even make it a flex fuel so that you can run either fuel and the pcm will compensate for you. My Tahoe is a flex fuel and I run it pretty much only on E85. It is nice to be able to run just gas if I get too low and I'm too far from an E85 station to get it. The new 80lb hr Ford Motorsport injectors would probably be enough using a return type fuel system and with Greg Banish's new DVD having the correct injector info your drivability would be as good or better than current.

 

I agree with the IAT issue, and feel that I will get limited returns due to the temps. That's why I figure that milling/swapping heads for smaller chambers makes the most sense. I like the idea of running E85, and I just checked on line for an E85 retailer...one of the stations I fill at sells it! I'll look into that conversion a bit!

 

Hi guys. Its been awhile since I gave an update. I have some good news about the transmission...its fine! The problem with the flaring on the 2-3 shift was the shift solenoid. I had Rick change both of them and it runs like new again.

With that confidence, I took the Yukon out to Sacramento Raceway today. It was 65* & just a real light tail breeze, and I left the street tires on for comparison purposes. My previous best was 12.707 at 105.91. That was with the GT2-3, JBA shorties with Magnaflow high flow catted y-pipe, and the 3.90 geared Auburn Pro 10-bolt that blew up. As listed previously in this thread, I swapped to Dynatech LTs/catted y-pipe, Speed Inc SC-1 cam (222/228, .566/.571, 114), 8" crank pulley/3.2" SC pulley, and the 3.42 geared G80 14-bolt. First run today was as follows:

RT = .180
60' = 1.82
1000' = 10.48 @ 87.91
1/4 = 12.57 @ 110.59

Second run blew the tires off. I decided not to burn off all the tread off my street tires and wrapped it up after that. Really relieved that the tranny was shifting fast and solid again.

So, next I'm going to have the 4.11 gears installed, and I still have the M&H 275/55R17 drag radials I picked up from Breeze. Then its back to track.

I have an HD video that I will convert and post up, as well as the time slip (but I need to run the time slip through a copy machine and darken up the printout--they gave me the weak a** yellow copy on my first run).

 

I hate that weak yellow copy damn it! Congrats Colby!

 

Ah geez, Margie! 11.34 @ 119?!! I'm falling behind FAST! lol

Thanks Bill. It was fun getting out to the track again...had the adrenaline jitters for 5 minutes after my first run.