Well I am officially DONE with the factory L31 JUNK top-end. When I put my L31 in the Express in 2006 I had to put the MFI spider in it. Well the spiders fuel pressure regulator is leaking into the intake. Went to remove the intake and the crappy plastic ended up cracking around the injector tower. I was going to just replace the regulator with an aftermarket equivalent and bump the fuel pressure toward 70 psi to combat my current 85% duty cycle, but after cracking the composite top, I am altering my thinking. My old 83 G20 is about to donate its TPI setup with its siamese ported Edelbrock 3817 base, siamese ported old style SLP runners, ported plenum and 58mm throttle body. I may also try to bolt the doug thorley tri-ys on, it looks like the Express chassis might just have the room I need to squeeze them in. I will be modifying the fuel rails to use AN fittings and move the fuel feed lines to the rear from the front by tapping the fuel rails for AN fittings. If I get industrious I may just pull the whole 350 out of the 97 Express and put my old 83s 383 in its place. It has been sitting over 3 years and until today had not run in 6 months, but a freshly charged battery, a few gallons of gas in the tank, twisted the key, even with a sticky IAC it fired right up and runs great other than the 1,600 rpm high idle. The tingy, ticking, banging noise is from the flowmasters on it, never have been a fan of them on this engine, but never felt like changing them. I am also considering picking up a propane dual fuel conversion setup for SFI and a DOT propane tank. It would be nice to be able to drive around for 1/2 or less the price of gasoline. The 383 put down 380+ RWHP and 430+ RWTQ the last time it saw the dyno and that was on a 7730 tune that had never even been datalogged or seen a wideband prior to the dyno day. I know I can squeeze more power out of the setup with the 0411. The one thing I know for certain EITHER way I am going to have to look for a 4L80E and see if I can get the gurus at HP Tuners to perform a 4L80E segment swap for me. The other thing I know is the Express is going to need some form of locking rear differential as the 3.42 open gearing is just not going to work.
https://www.youtube.com/watch?v=473BMNNnazM
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