Which profile?

The exhaust looks great but.....
DI has a good point, with air restriction of the Weber air filter. Maybe you could double stack two filters to get enough air flow...

The best thing you can do for your truck engine is compression and a distributor recurve. That will wake it up. The recurve will help a little right now with driveablity until you can bump up the compression.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Dist recurve? I understand in theory but how to do physically? Change springs, change weights??? I took apart points dist and saw numbers in vac canister arm and numbers on weights and bar above weights but below plate where points mount... what do they mean in relation to more/less advance....Im probably all over figuring this out but I live by "if it were a snake it woulda bit me"

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Life is never straight up, always a slant in there somewhere.

Found small vac leak in barbed fitting to pcv valve... Timing at 9 deg...currently have 55 idle jets, 145 mains, 170 air correctors and it screams (well tries hard) to about 70 MPH then it doesnt fall it just stops pulling and maintains... BETTER MUCH BETTER!

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Life is never straight up, always a slant in there somewhere.

Glad you're getting it worked out. I love to see slanted trucks. Nice flathead BTW. I have the same carb with a mopar ignition. Timing is 8-base with 28-full mech adv. I'm running 170 mains which I thought might be rich but the plugs are reading good. Let me know how your mixture works for you. I'm still trying to fine tune the fueling.
When my slant had the 1bbl, it wouldn't produce much past 3k. Now it pulls past and makes good power to 3800. It may make more but I don't push it too hard. I have history of destroying bearings on slants

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1985 Dodge B250 Van

145... thats the biggest I have...until Saturday!!! Its pulls great but flattens out around 38-4k havent hooked wide O2 yet, might do the Ole shut down at WOT and pull a plug tomorrow.
What are your other jets like/sizes?

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Life is never straight up, always a slant in there somewhere.

good timing on that question,, will be making a first road trip with the 83 D-150 this Saturday to get the bed / hood back from the shop,, that will be covered in a thread over in the gallery section..

but this is your thread,, so continue on,, did you ever get compression numbers?

Make sure to wrap that big head pipe. That will hold heat in the exhaust as long as possible. Back pressure is not required, and is actually not wanted. Velocity is what is needed. Keeping the spent gasses hot maintains volume, so keeps the velocity up.
Once you have good exhaust flow, the big jets will work better. They will also become a necessity.

Welcome to dot org!

CJ
From a hotel somewhere in New Jersey

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Part of Tyrde-Browne Racing

No compression yet...got to running good and started the fine tuning... I got all giddy and just wanted to drive it... I will get some numbers soon, it can only get better from here tho, runs pretty good. Will break RR tire loose for 6+' when i start in 1 and bury my foot... seems to be thirsty tho...like flushing the toilet, 38 should be rated in Gallons Per Flush!

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Life is never straight up, always a slant in there somewhere.

Thanks, Im having alot of fun here and with this truck thanks to this forum!

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Life is never straight up, always a slant in there somewhere.

I have been told by those who think they know that a smaller pipe increases velocity.

Sam

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This has been a fascinating read. That is a handsome truck indeed.

I got the biggest improvement in both power and economy on my slant from two things:

1. Running new wires pretty much everywhere, and bypassing thy ohm meter in the dash. I was getting about a two volt drop between the alternator and the 12volt side of the ballast resistor. There are just too many high resistance connections between the two on the stock set up. Take a VOM and check the voltage at various places along the path from alt to ignition, and see if and where it drops off. I think 1/2 volt is bordering on too much. Points ignition could tolerate this, but electronic ones will not.

2. Getting a good timing curve set up.I now have EFI which has a programmable timing curve, but the mechanical equivalent would be 10 base, 20 in the mechanical, 20 in the vacuum. The rates these come in are then played with until you optimize your setup. Springs do this on the mechanical, and an adjustable vacuum pod allows adjusting when the vacuum drop off affects timing. The AMOUNTS of advancee are all adjustable in a stock distributor, but not easily. There are numerous threads here on the forum discussing this issue.

I agree with whoever said it, your exhaust, while beautiful, is too big.

Let us know how the compression reading comes out.

Sam

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I think you now have exceeded the performance of a Holley 1 bbl.

ALLRITE! Cats-outta-tha-bag... Everything I own even my 2012 Ram RCSB HEMI gets modified...usually in the form of forced Induction... So im thinking the exhaust is fine for now... I do know from personal experience that the scavenging effects of velocity carried thru a proper sized exhaust does make a difference. Any one ever owned a BORLA exhaust with the restrictor plates for changing torque curves based on backpressure? I might weld in a flange and sandwich different diameter plates just to see...

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Life is never straight up, always a slant in there somewhere.

I think the exhaust is not hurting you that much. I would focus on timing and the electrical system. The electrical wiring is a pretty cheap thing to look into, and can yield some surprising gains.

You are on the right track in getting your fueling working better. I think the ignition needs more attention and focus. Once that is optimized, then go back to thinking about the exhaust.

Sam

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DCFAB.US

Sam's quote If you feel the exhaust gasses are cooling to quickly......I would be surprised with those 90 degree bends in the pipe. I run 2.5" all the way on my 74 Dart Swinger and was contemplating going bigger. I installed a Flowmaster HP2 up front which definitely keeps the system hot through to the Flowmaster 70. Mileage is awesome and power is very good. The system is super quiet!

Your question There is a entire section on this in the Engine FAQ. The slant like lots of initial timing producing good low end torque. Most old distributors are all gunked up and not working optimum. We usually don't change weights but length on the governor slots, springs and vacuum advance pods allow us to fine tune for max torque and mileage.

The first step is to plot your current curve as a baseline. Then the recurve changes will be meaningful.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG