L31 Extreme Budget Build

My plan is to have this P59 swapped and running this week. More mockup on the harness fitment. The GM PCM will reside on the driverside inner fender below the battery tray. I do not like that it will be under the battery, but fairly limited in large enough areas to mount it. The harness will run behind the steering shaft and I will secure it to the body with a cushion clamp or two to make sure it stays away from the steering shaft. I picked up some inexpensive universal mounting brackets for the PCM. The harness is almost the perfect length and lines up with the sensors and fuel injectors pefectly. Going to have to slightly change the crankshaft position sensor layout., but I am going to route it with the knock sensor wiring down the front of the engine.

L31MaxExpress said:

One at mine too today. Along with several Projection TBI throttle body units and a couple of BBK Vortec 80mm throttle bodies for the L31.

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Will the BBK TB work on the L30? Any benefit over stock on a 5.0 with exhaust and a mild cam.

Clammer said:

Will the BBK TB work on the L30? Any benefit over stock on a 5.0 with exhaust and a mild cam.

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Save your money and shave the lip on the stock throttle body.

Clammer said:

Will the BBK TB work on the L30? Any benefit over stock on a 5.0 with exhaust and a mild cam.

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I would track down a Volant intake first. I have a BBK but it was like a $15 junkyard score.

Browsing Car-Part.com paid off. This is on the way to me from Georgia. The elusive and monster 454 G30 air duct. Years ago on my TBI 350 in my 1983 G20 this added 10 whp swapping to the 454 air cleaner and ducting on a ~200 whp engine. This 350 moves a lot more air through it. Enough it pulls 2 in/hg manifold vacuum currently with the 4.3/305/350 TBI air cleaner and ducting. I wish I could find an affordible square body era tall air cleaner lid.

Yeah,I like Car-Part.com too. There are two local yards that will deliver listed there.

L31MaxExpress said:

Browsing Car-Part.com paid off. This is on the way to me from Georgia. The elusive and monster 454 G30 air duct. Years ago on my TBI 350 in my 1983 G20 this added 10 whp swapping to the 454 air cleaner and ducting on a ~200 whp engine. This 350 moves a lot more air through it. Enough it pulls 2 in/hg manifold vacuum currently with the 4.3/305/350 TBI air cleaner and ducting. I wish I could find an affordible square body era tall air cleaner lid.

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i have a tall lid from a squarebody if you can find me a 454 air duct from a 87-92 squarebody. i actually came across a 454 van air cleaner a few years back. wish i had done some more research probably worth more than $50 the yard wanted. I don't think the duct was with it though

tayto said:

i have a tall lid from a squarebody if you can find me a 454 air duct from a 87-92 squarebody. i actually came across a 454 van air cleaner a few years back. wish i had done some more research probably worth more than $50 the yard wanted. I don't think the duct was with it though

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Could be a scam could be legit. I kept seeing this listing when I was searching for the van one.

L31MaxExpress said:

Could be a scam could be legit. I kept seeing this listing when I was searching for the van one.

454 TBI Air Cleaner and Intake Duct - auto parts - by owner - vehicle automotive sale - craigslist

Do you still have the air cleaner assy. Yes, I do. Original GM air cleaner for throttle body fuel injected 454 Chevrolet GMC truck and Suburban $65 Hard to find cool air accordion plastic air intake...

nh.craigslist.org

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I reached out to the guy,he was willing to ship but had sold the duct I needed. I believe p/n is 15538410.

Nearly un-obtanium 454 air intake parts are in my hands. Ended up finding a Bosch filter for $5. Just going to run the 3.5" tall filter for now. If it ends up needing more airflow, I will swap on a tall lid and the 5.5" tall filter. This air cleaner housing was also built without the thermac tube or duct provision. Intake air will be as cool as it gets. The duct at the air cleaner is an 8" wide and 3.5" tall oval.


Compared to the necked down small block or V6 stuff it is a massive difference in airflow area as well as a larger filter. The smaller engine ducting necks down to 2/3 the height and width after the inlet elbow where the 454 setup expands after the elbow. The large oval duct elbow through the core support is the smallest portion of the 454 air intake area wise