99 L29 454 build

[L31MaxExpress]

When I changed my PS pump I got one without the EVO, tapped this connector up and out of the way. Didn’t notice any difference in steering without EVO.

I ran mine with the EVO disabled and it was much better feeling with it disabled. I forgot I had it unplugged when I put the 383 in and plugged it in. Seems to be working fine now as opposed to 10 years ago when I unplugged it. Got to a point it would not pump the pressure up at idle years ago. Odd but whatever, so I just left it.

 

[Scottm]

I got the skinny on the Electronic Variable Orifice. It varies the amount of pump flow for more assist at low speed and less assist at high speed. There is a steering speed sensor on the steering column that the pcm combines with vehicle mph input to control assist with the solenoid on the pump. My column sensor has probably failed, because I have over assist all the time. It was only used from 97-99. As with everything gm, the bean counters made sure it was too poorly made to be reliable, so it was quickly discontinued. EVO delete kits are a factory service item, number 19168825, still available on ebay.

 

[Supercharged111]

I got the skinny on the Electronic Variable Orifice. It varies the amount of pump flow for more assist at low speed and less assist at high speed. There is a steering speed sensor on the steering column that the pcm combines with vehicle mph input to control assist with the solenoid on the pump. My column sensor has probably failed, because I have over assist all the time. It was only used from 97-99. As with everything gm, the bean counters made sure it was too poorly made to be reliable, so it was quickly discontinued. EVO delete kits are a factory service item, number 19168825, still available on ebay.

PCM supplies VSS output to the EVO module, along with radio and a couple other things. The PCM gets the unfiltered signal which it buffers before spitting it back out.

 

[Scottm]

The swap is progressing, though never quickly enough. Right now I'm working on cheap ebay big block 'long tube' stainless headers, which don't fit and aren't really long enough either. I actually bought them over a year ago for my desert race truck, knowing they wouldn't fit it's smallblock, and was just expecting all along to heavily modify them. But the right side fit perfectly on the L29, so I decided to use them on the dually. They have 1-3/4 inch primary tubes, which is much better for a low rpm 454 than the usual 2 inch, but they are too short. The primaries really need to be 36-40 inches long for a 4,000 rpm truck motor. That normally means $1k Kooks or Stan's headers, but I'm doing it the cheaper hard way.

The left side doesn't fit at all because they are not for a 4wd... So I'm half way through reworking the left side to fit and add some length. It's actually easier than you might think. Plug access is already better, and I could have made it clear the oil filter pretty easily too, but I'm going to put on a remote filter. The old engine is still in for the header work, rather than grind and weld on the new one. I should have some pics tomorrow.

 

[Scottm]

It's time for me to get serious about the new fuel system. Will these accel injectors work? 30 lb/hr should be good for 400+ hp?

ACCEL 150830 ACCEL - Fuel Injectors - 30 lb/hr

ACCEL Performance fuel injectors provides precise control of fuel delivery & atomization for increased power and improved throttle response. They are all new units; not modified stock units or remanufactured from used cores. They feature a low-mass disc design that ensures accurate metering...

www.holley.com

 

[618 Syndicate]

The swap is progressing, though never quickly enough. Right now I'm working on cheap ebay big block 'long tube' stainless headers, which don't fit and aren't really long enough either. I actually bought them over a year ago for my desert race truck, knowing they wouldn't fit it's smallblock, and was just expecting all along to heavily modify them. But the right side fit perfectly on the L29, so I decided to use them on the dually. They have 1-3/4 inch primary tubes, which is much better for a low rpm 454 than the usual 2 inch, but they are too short. The primaries really need to be 36-40 inches long for a 4,000 rpm truck motor. That normally means $1k Kooks or Stan's headers, but I'm doing it the cheaper hard way.

The left side doesn't fit at all because they are not for a 4wd... So I'm half way through reworking the left side to fit and add some length. It's actually easier than you might think. Plug access is already better, and I could have made it clear the oil filter pretty easily too, but I'm going to put on a remote filter. The old engine is still in for the header work, rather than grind and weld on the new one. I should have some pics tomorrow.

They're probably for a square chassis if they're truck headers. Patriot's were the least expensive option I could find, and those are out of stock most places.

 

[Scottm]

This looks like the best deal in a big block ss header, but I think it may not fit the 4wd with gen 6 454:

https://www.hedman.com/product-detail/62820

 

[618 Syndicate]

This looks like the best deal in a big block ss header, but I think it may not fit the 4wd with gen 6 454:

https://www.hedman.com/product-detail/62820

Those are squarebody headers.

 

[Piratehunter]

It's time for me to get serious about the new fuel system. Will these accel injectors work? 30 lb/hr should be good for 400+ hp?

ACCEL 150830 ACCEL - Fuel Injectors - 30 lb/hr

ACCEL Performance fuel injectors provides precise control of fuel delivery & atomization for increased power and improved throttle response. They are all new units; not modified stock units or remanufactured from used cores. They feature a low-mass disc design that ensures accurate metering...

www.holley.com

I used these from 5 O, they sell on eBay a bit less than their site. https://www.ebay.com/itm/263315909406. They have been great and Blackbear tuned them right in

 

[Scottm]

There is a way to get exactly what you want - make it yourself! In this case I used a cheap ebay stainless bbc header for a good head start. I cut each tube off an inch or so from the flange, and cut the tubes off at the collector with staggered lengths to make it easier to reconnect them. I tacked the collector to a plate and clamped it to the crossmember for a fixed target. Here is the modified left side header, tacked up with steel mig wire. Plug access is better and it's more compact than the header was originally. Yes it's ugly! I could have made longer continuous sections with my tubing bender, but I don't have the time or extra material to experiment with. My bender can only make shallow bends in thin material because it wants to kink.

I bought a 6 ft straight piece of 1-3/4 x .049 wall 304 stainless tubing from Mcmaster Carr, and a couple U bends from ebay. It turns out I didn't need the ebay u bends, as the original header bends were enough. I did use most of the straight piece. The tacks were sanded off and the tubes were tig welded with 308l stainless filler and nitrogen back-gassing. Argon is better but a lot more expensive, and nitrogen works fine. The last pic shows my back gas flow meter setup. The next task will be to weld each tube to the collector, which will probably be the hardest part.