Engine intake manifold upgrade for the ‘36 Airstream

[pdentrem]

Not been happy with the carb that came with the ‘86 318 that replaced the original L6. Purchased a Edelbrock Preformer and a used QJet. Took a hour or so yesterday to remove and loosen the parts that need to be removed for the swap. Today removed the intake and did a quick inspection what can be seen. Yes the engine has roller lifters and the intake ports on the heads have been ported some time in the past. I will not change the camshaft for now as we need the car for the weekend coming up.

Huge difference between the carbs of course. I have experience with the Preformer intake and they are great for street use. Should make a better ride.
Pierre

 

[mmcmdl]

Ah , yeah . That'll make a difference alright . Had the Performer on an old Vette years back along with the Holley DP . Are you match porting the manifold to the heads ?

 

[pdentrem]

The intake ports on the heads are opened to the gasket. As for matching the manifold to the gasket and heads, the gain would be minimal unless a set of AFR or other heads were put on with a large cam and so forth.
Pierre

 

[pdentrem]

The hole is filled back in again. Pierre



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[pdentrem]

First start and it runs. Now to hook up vacuum gauge and set the carb and final hook ups etc.
Pierre

 

[pdentrem]

Went for a check ride for a couple hours, no issues found. No more stumbling at corners and lights. Improved starting when hot, no cranking, and even when cold starts right away. In this heat 90F, it should start easily anyways. Not a speed demon with a 2.29 rear gear(maybe) but much better than before.
Pierre

 

[mattthemuppet2]

very nice! It's incredible to see how constricted the original intake and carb were compared to the replacement

 

[pontiac428]

That rear gear ratio and engine bay were both designed for the inline 6. Ever thought about putting one back in? I ran a couple of good sixes over the years, mostly the Chevy 250 and 292, but also the Pontiac OHC 250, which was a smooth running engine. Any L6 would be a nice cause for retiring a 318. I've run a couple of those, and sent them down the road with new owners fingers crossed they'd make it to their new homes.

 

[pdentrem]

Never had issues with the 318, though Chrysler kept putting them into heavy cars and trucks where a 340 and up would of done better.
The 318 is from a 1986 D150. It has some work done to it as the heads have been ported, which surprised me. Being a roller cam, I can swap out the cam for a Hughes for a lot less money than I had originally thought when I talked with Hughes earlier. Still need to do a compression test and leak down.
The rear end and 904 3 speed AT is out of a 1986 Fifth Avenue, not original to the car. I am assuming on the gear ratio as that was the standard. I have still to get into that unit for inspection and service.
There is not a lot of room between the block and rad, but I were to go L6, I would use a 4200 out of a Trailblazer. Impressive engine as the 4 valve cylinder head is made to breath unlike all the earlier ones.
I am still going over the wiring, some original cloth wrapped and some more modern stuff. Added a fuse panel to split the different systems apart to ease troubleshooting. There were only 3 fuses, radio, turn signal switch and main feed. Lots of wires left hanging, powered or not and very sketchy.
On the bonus side, all the original gauges are working and when compared to the set shown in the photo, fairly close in their readings. I was a bit concerned with the oil and water temperature gauges as those are the critical ones. Amp/volts is less of a problem until the alternator packs it in!
Pierre

 

[pontiac428]

The 4200 makes almost 300 hp with a flat L6 torque curve and 20 mpg with efi, a 4 speed, and plentiful parts... yes please!

The 1986 D150 was an air injection motor that ran not one but two Rochester smog pumps. Those heads had to come from an older motor sans injection ports in the exhaust and EGR uglies in the castings. The bottom ends are pretty tough and they pull nice and steady on shallow rear end gears.