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  1. L31MaxExpress

    L31 Extreme Budget Build

    I temporarily permenately sealed it and the air divert air port with aluminum high heat duct tape used for HVAC stuff.
  2. L31MaxExpress

    L31 Extreme Budget Build

    Luckily it does not and I pulled the semi circular baffle and the thermac flap out of the air cleaner. Under ~4,000 rpm the TBI SBC air cleaner is not too restrictive though, under 1 in/hg loss. Above 4,000 it starts building vacuum quickly. No surprise though, it was engineered for a 350 that...
  3. L31MaxExpress

    L31 Extreme Budget Build

    Same as a 4.3 or SBC TBI truck, 5.5 x 2.5. By comparison the big block one is 8 x 3.5. Edit, I just corrected it with the actual dimensions of both. The elbow through the core support is 6 x 3" and the SBC intake duct narrows substantially after the elbow. The big block duct is just proving to...
  4. L31MaxExpress

    Best Intake gaskets

    They have not lasted at all for me. 3-4 years and they are junk. I still have the Vortec TPI 383 that was in the 1983 G20. It still runs perfectly with ~15 year old 7235s on it.
  5. L31MaxExpress

    L31 Extreme Budget Build

    I have not remodeled the engine in DD2003 but when I was planning the L31 injection prior to finding the PF4 and prior to using the dual plane MPFI manifold and the tri-Ys, I modeled it with a Sequential EFI manifold, 650 cfm of throttle body flow and a decent exhaust without headers. 492' cam...
  6. L31MaxExpress

    L31 Extreme Budget Build

    So I confirmed from a previous screenshot, key on MAP is -0.6 in/hg here. The TH400 is shifing at ~5,700 rpm with the throttle pinned. MAP is reading -2.2 in/hg at the shift point. Intake manifold vacuum thus 1.6 in/hg at the shift point. So the OE SBC TBI air cleaner and ducting are fairly...
  7. L31MaxExpress

    L31 Extreme Budget Build

    I put the van specs in, the power curve from DD2003 for the 350 I was building and it spit out that chart.
  8. L31MaxExpress

    L31 Extreme Budget Build

    No but I want sleeper status. From the front of the engine compartment the PF4 hides out very well especially with the dual plane manifold. If it were to go down the track ever and they were to lool under the hood while the engine was cooling down, I want people scratching their head as to how a...
  9. L31MaxExpress

    L31 Extreme Budget Build

    Looking back earlier, this runs about exactly how I expected it to. Based off the Dragtime calculator on Wallace racing. Was a cool calculator to play around with. Converter is stalling right in line with the calculator too. I used GMs rated stall speed and the stock 305s approximate torque...
  10. L31MaxExpress

    L31 Extreme Budget Build

    I did, but it is a tight fit. Have not adapted it over. I really want to find the factory 454 van air duct still as I have a 454 RV/Van air cleaner already and I like the more stock appearence under hood. I will probably end up using the dual snorkel on the 1980 Z28 build. I have another L31...
  11. L31MaxExpress

    Best Intake gaskets

    I ran and still run the Edelbrock 7235s but nice catch on the 1255s.
  12. L31MaxExpress

    L31 Extreme Budget Build

    I had one in my 83 with the TBI 350. It is the air cleaner assembly itself and ducting size. It is fairly small. A 454 air cleaner and intake duct was +10 rwhp on a near stock L05 engine. The 454 intake duct is roughly 2.5x as large.
  13. L31MaxExpress

    L31 Extreme Budget Build

    I also set the cruise at 65 mph rolling down the highway in minimal traffic, took my foot off of the pedal and it held ~65 mph beautifully. Will be nice to have on the long drives for the Power Tour.
  14. L31MaxExpress

    L31 Extreme Budget Build

    Drove it around for a couple hours today. Got warm this afternoon here. With the ac on and the added engine and engine compartment heat it was a little more doggy than it was last night in the 40ish degree air. Only ran up about 58-59% injector duty cycle. Every engine I have ever had hates...
  15. L31MaxExpress

    Complete Exhaust System From the Head to the Bed 1990 C1500 Single cab Short bed

    I would try it....At $190 the muffler and hardware alone are probably worth it. https://www.holley.com/products/exhaust/exhaust_systems/hooker_blackheart/parts/BH2467
  16. L31MaxExpress

    L31 Extreme Budget Build

    In 1986 when they went 1 piece rear seal. Even the 4.3L is externally balanced in the rear.
  17. L31MaxExpress

    L31 Extreme Budget Build

    It is a two piece driveshaft, I pulled the carrier bearing mounting bolts and it became real floppy. I have a 1-piece rear seal engine and that TCI flexplate is for a 1-piece rear seal engine, except for one that has been completely internally balanced.
  18. L31MaxExpress

    L31 Extreme Budget Build

    Finished swapping the flexplate a little while ago. Engine is silky smooth now, only took a couple of hours to change out. I supported the engine oil pan with a floor jack. Used a piece of plywood on it to give it more surface area to protect the pan. I removed the carrier bearing mounting bolts...
  19. L31MaxExpress

    L31 Extreme Budget Build

    I have had a very minor vibration in this that was getting much worse with the torque converter bolted up. Well I feel dumb at this moment. Completely missed that the TCI flexplate I had and used is for an internally balanced 1-piece rear seal engine. I did not even realize that was a thing...
  20. L31MaxExpress

    L31 Extreme Budget Build

    I put 10 gallons in it with the fuel gauge in the orange low fuel band bringing it straight up to 1/2 tank. Beat the snot out of it for ~15 miles and fuel level dropped a needle width, lol. Nice to have a GM of this era with a functioning gas gauge. When I put the 93 octane in the tank, I...
  21. L31MaxExpress

    L31 Extreme Budget Build

    Lol Still have to pull the 4L85E in the 97 to fix the fluid leak. Now that this 87 is up and running time to get on that.
  22. L31MaxExpress

    L31 Extreme Budget Build

    Cruised it around a bit. This 350 is an absolute animal. It comes on strong even in 3rd gear at 70 mph. I checked the speed using the PF4s GPs speedo, the van speedo is about 4 mph fast at 70 mph. 70 mph GPS is actually 2,750 rpm. I do not have the downshift solenoid hooked up yet, so it is a...
  23. L31MaxExpress

    L31 Extreme Budget Build

    Finished up most of the little things today. Fabricated a proper coil wire to replace the Vortec or LT1 plug wire I had on it, fixed a small oil leak on an oil cooler fitting, cleaned out the back of the van, removed those 2" OE replacement style tail pipes. I have the exhaust tucked in so well...
  24. L31MaxExpress

    L31 Extreme Budget Build

    Here is a screen capture at idle. Belt idler is making a bit of noise that I can now hear with the quieter exhaust. The AFR fluctuates around stoich fairly substantially.
  25. L31MaxExpress

    L31 Extreme Budget Build

    It might especially if the pressure is raised a bit but not worth putting in by itself unless the tank is coming out for other reasons.

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