We finally got around to installing the 4.10s Thurs night and we had the first track run last night. I'm guessin' the air was in the high 50s-low 60s... and she ran a best 7.98-1.78 at 87mph.

The first thing I noticed was she broke loose out of the hole for the first time since I installed the Mickeys and she STILL posted an 8.06-1.78... I had been running 23 lbs, so immediately took it down to 17 lbs which solved the problem, except for one small squeak, which I attribute more to my being askew of the groove when I staged up on that run...

Second run was 7.98-1.78 and we stayed there pretty much for the rest of the night.

The second thing I noticed was that the tune/set-up had changed dramatically.

She now tickles the rev limiter coming out of first and smashes against it from second/third, which now comes up at about 450'. Before, she crossed thru the trap at the high edge of second; if I stayed in it, she would shift into third just as I crossed thru the time-boards... probably 30' beyond the trap laser.

The third thing, as I eluded to above, is that she hangs in second WAY too long... she's nosing over badly at the top of second before she pops third, she's just hanging there...; so I've no doubt that this is costing us big in ET. It's the same for first to second, just not as bad, so combined, I'm guessin' this could be as much as a tenth.

She has however blown the paper header-gaskets now (kids, this is one of those rooky 'mistakes' that the gurus will elude to when you're inquiring about doing your first rebuild ... GET THE ALUMINUM CRUSHERS!) and while I'm fixing that I am going to send the PCM back to Bryan at PCM-for-Less and have him change up the tune to accommodate the 26" Mickey's and the 4.10s. I expect that will put us where we need to be for the moment...

I've seen a lot of comments by guys on this site and others who have waved people off the 4.10s... and some that have installed the 4.10s and said they didn't really see a lot of change in ET with the 4.10s...

I'd just like to speak to those for a moment... I think that the tune is the reason is why the new 4.10 drivers are having problems... My Speedometer is WAY off now; looks like 20-25%, so anything that computes with consideration of the indicated speed is going to be screwed up, so a re-tune is mandatory, as far as I can tell.

As to the waving off of the 4.10 set-up... First let me say that my primary goal is 1/8th mile ET and heads-up 1/8th mile drags... Second, I DO, on rare occasion, enjoy some light 'street fishin;' low-end, light to light, 0-60 kills... because, well... they're just 'ma thang...' I'm decidely not interested in or concerned with fuel mileage OR highway cruising...

So, with that said, let me just say... I am LOVIN' THE 4.10s...

VIVE LE DIFFERENCE!


1st now comes and goes in a neck snapping moment... second remains a power-house and 3rd gear is DEADLY... drop her into 3rd and @ roughly 55 she sits at 3500ish rpms; so she is right in the 'pardon me while I kick your ***' zone... from 55mph in 3rd, it's unlikely you'll be offended by too many fly-bys, assuming you've some warning; at 3500 rpms ya just throw the hammer and stand the f&*#^ by for heavy acceleration... 'Sheeees GONE!

 

sounds like you need a retune there buddy

 

i love my 4.10s. what stall do you have? get it re-tuned and you will see more improvement. i was hitting 1.6X with just bolt-ons and 3600

 

Kudos to you for sticking to your guns and building your car EXACTLY the way you want it. The tune should help you out immensely. What sort of mods do you have done to your car?

 

Thanks fellas... and yeah the PCM goes back to Bryan when I get home...

see sig for mods...

 

You still need more stall OVA

 

PUCK! LOL... Ain't that the truth Brother... and it's comin' I'm just waiting on the right buy for a well loved 9" 3600ish to come on line.

I think the re-tune will get us back in the hunt in the mean time...

Also, after I fixed the header gaskets last night, I found she's developed a knock... sounds like bottom end, but it disappears under load and the oil pressure is rock solid... any ideas?

 

Was the car fully warmed up?

First thing I would do is double check the oil pressure with a mechanical gauge - there is a nice empty spot on the 94+ right above the oil filter, which is where the factory sensor is on the 93's.

 

Im thinking of going with 4.10s myself. Ive already got 3.73s and they made a nice difference. What i notice with the 3.73s, when i spray it she'll grab 4th gear about the 1000ft and man it pulls hard for that last 320 ft. I was thinking it would grab it sooner and give me some more MPH with 4.10s. With stock 3.23 it would trap 108 MPH, with 3.73s it started traping 115 MPH. Im quite sure the 4.10s def wouldnt slow me down. Oh whats it tacking at 60 cruising. I was at 2000 to 2100 with 3.73s.

 

The OP is running an auto. It is "generally" considered too much gear for an auto to run 4.10's, but in his case (an 1/8th mile car) it is working perfectly. You run an M6. 4.10's are the best gearset for them hands down.

 

I had 4.10's in my car for a little while, It was great on motor but I would run out of gear on the bottle so I switched to 3.42's

 

i see a few mismatched parts on your build that may not be giving you the maximum performance:
header tube size is a bit large at 1-7/8(for the set up)
2500 stall is barely enough to satisfy a stock Lt1
of course the lack of tune as mentioned prior

 

Yeah it's warm... and I'll check the OP with a mechanical gauge.

It was late when we finally got the crushers in and tightened down... so all I was able to do was throw a scope on the top end and that was inconclusive...

I'll post what we find out, when I get back.

 

ROFL... If you hate the 1 7/8th tubes, the dual 3" dumps should be drivin' ya nuts. The tubes are fine... I'm of the better 'breathin' equals better performance' school and they'll be even better with the 21 degree heads coming next spring; the stall was a rookie mistake. I'd never driven one and was concerned with streetability and when I find a deal on a previously loved, name-brand 9" 3600 in excellent condition when I have the coin, I'll be all over it.

In the mean time I've got this knock to work out, which is killin' my 4.10 buzz...