L31 Extreme Budget Build

[Orpedcrow]

How do you think those hookers flow versus stock logs or shortys? They definitely look good

 

[L31MaxExpress]

How do you think those hookers flow versus stock logs or shortys? They definitely look good

I think they will flow alot better than the OEM manifolds and probably better than alot of shorties. The stock replacement style shorties neck down into an opening the size of the stock donut gasket. The shorties may offer a little better scavenging, but they all neck down to that ~2.0-2.25" opening to fit the stock exhaust. I wish they had a flange to reuse the stock donut, because the HD exhaust is a bit more open than the shorties at the flange. I think the Holley Hooker manifolds will easily make as much if not more power than most shorties. My buddy uses the Summit LS version of these on most of his LS C10 swaps and they seem to do quite well even at 6,000-6,500 rpm. They cast these manifolds with Molybendum Silicon in the material and the casting is incredibly smooth. These also have raised D-port exhaust ports as well which makes them nice for engines that have 0.100" raised exhaust ports like the Edelbrock ETec heads do.

The SBC shorties are not alone in this aspect. Another buddy found out that the LS shorties kept him from being able to run the 3" LQ4 HD front exhaust piping and their integral flanges were smaller than the internal opening of the stock piping so that they would mate to the stock 1500 LS engine piping without using a donut.

That being said the shorties that are more of a mid length that come with 3 bolt 2.5" flanges to build an exhaust and ditch the factory Y-pipe probably outflow these.

At this point I kind of want the ceramic coated Chevy II Tri-Ys I saw for $200 at Summit. I am 99.995% certain they would bolt on and clear every point of the G20 van chassis. Then again I have a set of GMT400 JBA big block stainless long tubes I paid $300 for from Summit still hanging on the wall in the shop for the 8.1L Tahoe. I have the coated GMT800 8.1L Burb/Avalanche Edelbrock shorties on the engine. The suburban/avalanche headers tucked in to the frame tighter to the engine than the truck ones with the Allison so they barely clear a GMT400 frame.

 

[L31MaxExpress]

I find too much in the scratch and dent. One reason though I am glad I do build GM stuff especially SBC. You would not find some of these things with some other engines. Summit does clear out alot of LS and Ford stuff too, but nothing like they have for a basic old SBC. The pan did not come with any hardware, but SAE allen key head cap screws and washers are cheap at the local Ace Hardware. I like allen key screws on transmission pans because it makes it easy to remove with a simple drill for filter changes. The drain plug alone and not spilling a face full of fluid into your eyes is worth it. I remove the leaky steel pans the cleanest way possible, with a punch and a hammer.

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[L31MaxExpress]

This is the point I left it at when I walked away. Still need to clean up that upper plenum and replace the cap and rotor on that distributor too. I have my good old analog test fire gauges already attached too. Love a good mechanical temp and oil pressure gauge for the first run.

PS I will properly route the wires the exact way GM calls for them to be when I find a set of the stock brackets.

Also last minute change, I am going with a distributor and DBC rather than 24x and DBW even though it requires some harness changes. I am already having to rework the harness that ran the LS anyway. OE pedal and OE pedal bracket allow me to put the kickdown detent switch in the OEM location for a TH400. The TBI system handled the kickdown when it was stock via a relay. With the 6.0L I controlled it with the shifter. It will be nice to have a functioning automatic kickdown at WOT again. With the TH400, 3.08s and 28" tall tires it has some really long legs in 1st & 2nd. I have a set of B&M or TCI weights and springs to recalibrate the governor from my 700r4 days. I will probably shoot for 5,200-5,500 @ WOT (that is 55+ mph in 1st and 95+ in 2nd and now you why a LS that did not make its torque peak until 4,500 rpm was a dog) and then play with the adjustable modulator to get the part throttle where I like it best

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[L31MaxExpress]

I discovered a few things this evening. First 4L80E factory pan bolts are an exact replacement for vortec water pump pulley bolts. Second that the 1987 G20 power steering pump I still had laying in a pile of accessory junk was an easy fit on the vortec brackets. Third I found an oil pressure pipe and sending unit. I also found a 2nd new style power steering pulley, guess I somehow ended up with 2 when I built the 97. I love the new style pulley because you can get at the bolts without having to first remove said pulley. Makes replacing a pump easier in chassis. Finally I found a nearly new drivebelt hanging on the wall. Perks of owning, working on and parting out many of these trucks over the years.

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[L31MaxExpress]

Final picture for the night. 01 or 02 Astro Van harness from a van I parted out that had a bad 4L60E. Dimensionally the harness is not bad, and it is already setup for an 0411, PCM controlled alternator, the right ac wiring and what not but definitely needs some new connectors in places and some modification. Obviously the injector connector and knock sensors will need to be re-wired. Luckily I have many cut up parts harnesses so that I can replace damaged connectors and extend things to where they need to be. The Astro van harness is also a solid foot or so longer than the truck harness giving me freedom to mount the PCM where I need to. I will re-use the Astro van fuse box and power the van through its main fuses rather than the cluster of fuse links GM used on the G20 vans. I will also update this van to the Express van blower resistor and blower motor because they just move more air. Removing the rear 02s and the ABS gives me some added wiring and relays already part of the harness to run the flex fuel sensor and electric fan clutch. There is already 10 ga red/black power and ground wire attached to the ABS relay going way back into the harness. Perfect starting point for upgrading the fuel pump wiring.

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[Scottm]

It's nice that the smallblock ac/ps accessory bracket is aluminum. The bb one is cast iron and weighs about 30 lb.

 

[L31MaxExpress]

It's nice that the smallblock ac/ps accessory bracket is aluminum. The bb one is cast iron and weighs about 30 lb.

Oh I know, but honestly I prefer the cast iron. My 8.1 has an alternator setup that has to weigh 70 lbs. Steel bracket, 2 alternators, 3 idlers.

 

[Supercharged111]

Question: could you swap a normal reservoir onto that van pump? The van unit looks the same as what is is my dad's Monte, which came from a motorhome. I'm hoping I can just zap this non-hydroboost reservoir that came off my 1500 onto that pump. I have no need for a remote reservoir on the Monte, PS pump access is super easy on it.

 

[L31MaxExpress]

Question: could you swap a normal reservoir onto that van pump? The van unit looks the same as what is is my dad's Monte, which came from a motorhome. I'm hoping I can just zap this non-hydroboost reservoir that came off my 1500 onto that pump. I have no need for a remote reservoir on the Monte, PS pump access is super easy on it.

Reservoir swaps right over. I would pick up a seal kit and reseal the thing just to make sure it does not leak though.