The Struggle
Member
- Joined
- Jan 13, 2015
- Posts
- 38
- Reaction score
- 83
- Location
- Converse, TX
- First Name
- Blaine
- Truck Year
- 1981
- Truck Model
- K10
- Engine Size
- 350
Hey guys!
You're the first to go to when I have hard to answer questions so hopefully I can get some help again (thanks for all the support in the past!) Below is a description of my truck, engine and the issues I running into. (Forgive me on the long write up).
Truck: 81 k10 (3/4 ton axle swap) th400, 2500 stall boss hog converter, 360 ci sbc, 4:10 gears, 35" tires (4" lift)
Engine:
Rotating Assm: Eagle cast crank(stock stroke), I beam rods (stock length) and FM Pistons
Cam: Camshaft, Hydraulic Flat Tappet, Advertised Duration 298/304,.466/.487 LSA 114 + adjustable timing chain set straight up.
Summit vortex heads: 2.02 int./1.90 exh. (64cc chambers) Springs rate at .525 max lift, 1.5 roller rockers+stud girdles
Intake: RPM air gap with edelbrock 750 CFM+ electric choke. (No carb spacer)
Distributor: Summit brand with 10 degrees vacuum adv. 10 degrees full mechanical @1500 rpm (6 degrees at 800 rpm) yikes it comes in fast!
I have initial timing set at 24 degrees with the distributor dropped in (pointing to number 1 cylinder) at 24 degrees BTDC. Total timing @34 degrees for the sake of the fast burn heads on 93 octane.
Truck runs smooth at idle and will rev all the way through the power band range (2,500-6,000) I don't get it past 4,500 in park since I like my toy. Putting it in gear it'll slightly stumble and become sluggish coming off the idle circuit. (I believe I'll need to adjust the carb to pull more air in right past idle via small 1/8" throttle plate holes but that's after I expend all other options. That's just a small tinkering issue since I have another 750 eddy to tear up from a friend instead of my brand spanking new one. So continuing on....
She'll idle at 1,000 -1,100 in park and 750-800 in drive. I can punch it a spin the tires and get up to 3,000 rpm and the engine stays at that RPM through all 3 gears with foot to the floor at WOT. I believe it may be a timing issue since power just stops and remains steady 3k... But no pinging or popping from the engine or exhaust. My th400 has been topped off with 6 quarts of ATF, 1" below the fill plug of ATF for the np208 and 4 quarts for the TQ converter. The tranny still is not off my issues list so I added about a half quart after driving it since I have cooling lines and an internal cooling tube in the radiator.
My assumptions:
1.) The Tranny is too full! (I have not drained any of the possible 6.5 quarts that are in it).
2.) The truck has too much advance and is lighting off too early at WOT limiting the RPMs due to the distributor coming in too fast. (Needs retard a few degrees possibly).
3.) Carb needs tuning for the off idle stumble. (Yes I tuned it at a max 15 " of vacuum for this cam after changing out the metering rods and springs and adjusted the A/F screws to max vacuum then back a quarter turn) to attempt to rid the off idle stumble (it partially helped and is manageable. No the linkage adjustment works and is snug on the accelerator pump lever and the idle screw is closed enough to where I can kill the engine via closing one A/F screw. Adjusting the accelerator pump does not help much if at all. It still hesitates when cruising around 1,100-1,800 rpm and then wakes up right after 2,000 rpm.
Where do you guys think I should start at? 1,2,or 3? I'm not set in my ways and am open to adjusting many things and resetting timing to other adjustments. Just want her to run right.
Below are some pics of the truck for viewing pleasure since you read through my crap and problems. Any help would be greatly appreciated!
You're the first to go to when I have hard to answer questions so hopefully I can get some help again (thanks for all the support in the past!) Below is a description of my truck, engine and the issues I running into. (Forgive me on the long write up).
Truck: 81 k10 (3/4 ton axle swap) th400, 2500 stall boss hog converter, 360 ci sbc, 4:10 gears, 35" tires (4" lift)
Engine:
Rotating Assm: Eagle cast crank(stock stroke), I beam rods (stock length) and FM Pistons
Cam: Camshaft, Hydraulic Flat Tappet, Advertised Duration 298/304,.466/.487 LSA 114 + adjustable timing chain set straight up.
Summit vortex heads: 2.02 int./1.90 exh. (64cc chambers) Springs rate at .525 max lift, 1.5 roller rockers+stud girdles
Intake: RPM air gap with edelbrock 750 CFM+ electric choke. (No carb spacer)
Distributor: Summit brand with 10 degrees vacuum adv. 10 degrees full mechanical @1500 rpm (6 degrees at 800 rpm) yikes it comes in fast!
I have initial timing set at 24 degrees with the distributor dropped in (pointing to number 1 cylinder) at 24 degrees BTDC. Total timing @34 degrees for the sake of the fast burn heads on 93 octane.
Truck runs smooth at idle and will rev all the way through the power band range (2,500-6,000) I don't get it past 4,500 in park since I like my toy. Putting it in gear it'll slightly stumble and become sluggish coming off the idle circuit. (I believe I'll need to adjust the carb to pull more air in right past idle via small 1/8" throttle plate holes but that's after I expend all other options. That's just a small tinkering issue since I have another 750 eddy to tear up from a friend instead of my brand spanking new one. So continuing on....
She'll idle at 1,000 -1,100 in park and 750-800 in drive. I can punch it a spin the tires and get up to 3,000 rpm and the engine stays at that RPM through all 3 gears with foot to the floor at WOT. I believe it may be a timing issue since power just stops and remains steady 3k... But no pinging or popping from the engine or exhaust. My th400 has been topped off with 6 quarts of ATF, 1" below the fill plug of ATF for the np208 and 4 quarts for the TQ converter. The tranny still is not off my issues list so I added about a half quart after driving it since I have cooling lines and an internal cooling tube in the radiator.
My assumptions:
1.) The Tranny is too full! (I have not drained any of the possible 6.5 quarts that are in it).
2.) The truck has too much advance and is lighting off too early at WOT limiting the RPMs due to the distributor coming in too fast. (Needs retard a few degrees possibly).
3.) Carb needs tuning for the off idle stumble. (Yes I tuned it at a max 15 " of vacuum for this cam after changing out the metering rods and springs and adjusted the A/F screws to max vacuum then back a quarter turn) to attempt to rid the off idle stumble (it partially helped and is manageable. No the linkage adjustment works and is snug on the accelerator pump lever and the idle screw is closed enough to where I can kill the engine via closing one A/F screw. Adjusting the accelerator pump does not help much if at all. It still hesitates when cruising around 1,100-1,800 rpm and then wakes up right after 2,000 rpm.
Where do you guys think I should start at? 1,2,or 3? I'm not set in my ways and am open to adjusting many things and resetting timing to other adjustments. Just want her to run right.
Below are some pics of the truck for viewing pleasure since you read through my crap and problems. Any help would be greatly appreciated!
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