I'm messing with you. I just like the idea of a carb on an old street truck.
CK5
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Well, I chickened out and didn't swap the manifold. I wanted to try and tackle only what I could accomplish in the time I had. I was a little concerned that changing so much could lead to trouble if I couldn't get it to start afterwards. I guess I'm getting too old and cautious.
I started out with swapping the carb. I went with a Street Demon. We had a Speed Demon carb on our 'cuda, and I always liked it. The Street Demon is supposed to be a modernized carb. Incidentally, Demon is owned by Holley nowadays. They recommend using a spacer/adapter for factory spread bore manifolds.
This adapter was made by Mr Gasket. I ended up getting my own bolts. For some reason the allen socket didn't quite fit my standard allen wrenches, almost like it was metric even tho the threads are 5/16. Then the studs (which are really bolts that fit into a hex recess from the bottom) weren't quite long enough.
Goofy thing with this carb is the fuel inlet on the back side. Unfortunately I cut the steel line before I remembered this because I could have left more of the original steel line and still had room for the inline fuel filter. Still, it works fine like it is.
I actually had a leak at the hard line where it connects to the pump. Did the old trick of loosening it up and re-seating it and sure enough leak fixed. Always surprises me when that trick actually works.
The next thing I did was pull the driver side valve cover because it was leaking. Plus this made it easier to find TDC for the distributor swap. I even painted the valve cover while it was off; you may see it in some of the pictures. Not much to show there. I did use the custom length spark plug wires. It's a little time consuming but I like the results better. I probably didn't need to replace the distributor but I've been stranded by dead distributors more than anything else. Plus I couldn't tell what brand it was or how it was curved or anything. By putting one in myself, I know what I'm starting with.
The truck already had HEI, oddly with a blue cap. It would have come with a points distributor. There's a lot of debate about which years they started putting HEI in trucks, but I'm sure mine didn't because the sticker on the core support lists a dwell setting.
I still wanted to block off the EGR so I just cut a piece of 3/8" thick steel plate and used some RTV to seal. The style on the '73 is held on with a clamp, kinda like a distributor.
I started with this (stupid tiny air cleaner):
This is it now with 1 fresh painted cover.
I had a hell of a time finding a breather for the passenger valve cover. It was running 2 PCV valves, one in each cover, so I had to find a breather to fit a 3/4" PCV hole. I had 3 laying around and they were all too big. Luckily found one at the second parts store I checked.
Last thing I need to do is find power for the electric choke.
I started out with swapping the carb. I went with a Street Demon. We had a Speed Demon carb on our 'cuda, and I always liked it. The Street Demon is supposed to be a modernized carb. Incidentally, Demon is owned by Holley nowadays. They recommend using a spacer/adapter for factory spread bore manifolds.
This adapter was made by Mr Gasket. I ended up getting my own bolts. For some reason the allen socket didn't quite fit my standard allen wrenches, almost like it was metric even tho the threads are 5/16. Then the studs (which are really bolts that fit into a hex recess from the bottom) weren't quite long enough.
Goofy thing with this carb is the fuel inlet on the back side. Unfortunately I cut the steel line before I remembered this because I could have left more of the original steel line and still had room for the inline fuel filter. Still, it works fine like it is.
I actually had a leak at the hard line where it connects to the pump. Did the old trick of loosening it up and re-seating it and sure enough leak fixed. Always surprises me when that trick actually works.
The next thing I did was pull the driver side valve cover because it was leaking. Plus this made it easier to find TDC for the distributor swap. I even painted the valve cover while it was off; you may see it in some of the pictures. Not much to show there. I did use the custom length spark plug wires. It's a little time consuming but I like the results better. I probably didn't need to replace the distributor but I've been stranded by dead distributors more than anything else. Plus I couldn't tell what brand it was or how it was curved or anything. By putting one in myself, I know what I'm starting with.
The truck already had HEI, oddly with a blue cap. It would have come with a points distributor. There's a lot of debate about which years they started putting HEI in trucks, but I'm sure mine didn't because the sticker on the core support lists a dwell setting.
I still wanted to block off the EGR so I just cut a piece of 3/8" thick steel plate and used some RTV to seal. The style on the '73 is held on with a clamp, kinda like a distributor.
I started with this (stupid tiny air cleaner):
This is it now with 1 fresh painted cover.
I had a hell of a time finding a breather for the passenger valve cover. It was running 2 PCV valves, one in each cover, so I had to find a breather to fit a 3/4" PCV hole. I had 3 laying around and they were all too big. Luckily found one at the second parts store I checked.
Last thing I need to do is find power for the electric choke.
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I had that same issue with finding a 3/4" breather a few yrs back on a small block truck I flipped.
I like Amazon because I hate having to go to stores, but sometimes you need something quicker. But then having to visit 2 parts stores to find what I need reminds me of why I order online.
Ditto
I installed the Square Body Syndicate bowtie on the grill. It looks very nice!
Truck has set since Saturday. I don't think it's gotten above 40F in the mean time and this morning was foggy and 17F. Thought I would see how well it started. Stomped the pedal cranked for just a bit and started up and idled. Very happy.
What did you use to glue it on?
We have a bunch of double-sided VHB (Very High Bond) tape here at the shop. I used the thinnest stuff we have.
Kind of a warning, it was a pretty exact fit so you got to get it lined up right. It also took quite a bit of work to remove the old adhesive with a plastic scraper and adhesive remover.
Kind of a warning, it was a pretty exact fit so you got to get it lined up right. It also took quite a bit of work to remove the old adhesive with a plastic scraper and adhesive remover.
All is right in the charging world again. New 12SI 100amp alternator and Deka AGM battery. FYI difference between old 10SI and new 12SI.
The 12SI has better cooling and higher rating, straight bolt-in swap; that's why I went that direction. Although the 12SI is metric.
This truck pulls really strong. I was thinking it might have 3.73 rearend but yet it runs a touch under 2200RPM @ 65mph. After some interwebs searching and gear calculator verification, I discovered it has 2.76 gears which was standard for 10blt equipped C10's. Man I'm impressed with the acceleration. I don't know if it's the Street Demon carb or what. That carb has the smaller primaries like a qjet.
I also learned something slightly annoying after further searching. I couldn't for the life of me figure out how to fold the seat back forward. Turns out before 75, they didn't fold.
Makes me more motivated to replace it with something else. Gonna keep it bench, but I think I'll look for something from the 90s.
The 12SI has better cooling and higher rating, straight bolt-in swap; that's why I went that direction. Although the 12SI is metric.
This truck pulls really strong. I was thinking it might have 3.73 rearend but yet it runs a touch under 2200RPM @ 65mph. After some interwebs searching and gear calculator verification, I discovered it has 2.76 gears which was standard for 10blt equipped C10's. Man I'm impressed with the acceleration. I don't know if it's the Street Demon carb or what. That carb has the smaller primaries like a qjet.
I also learned something slightly annoying after further searching. I couldn't for the life of me figure out how to fold the seat back forward. Turns out before 75, they didn't fold.
Makes me more motivated to replace it with something else. Gonna keep it bench, but I think I'll look for something from the 90s.
My 78 had a fold forward seat. I had a fool box that fit behind it. Was 1/2 the hight of the seat.
Yeah, that's what I was planning to do. I did find the seat slides, so maybe I'm supposed to just slide the whole thing forward. There are tools or something clunking around behind the seat.
What size tires?All is right in the charging world again. New 12SI 100amp alternator and Deka AGM battery. FYI difference between old 10SI and new 12SI.
View attachment 288265
The 12SI has better cooling and higher rating, straight bolt-in swap; that's why I went that direction. Although the 12SI is metric.
This truck pulls really strong. I was thinking it might have 3.73 rearend but yet it runs a touch under 2200RPM @ 65mph. After some interwebs searching and gear calculator verification, I discovered it has 2.76 gears which was standard for 10blt equipped C10's. Man I'm impressed with the acceleration. I don't know if it's the Street Demon carb or what. That carb has the smaller primaries like a qjet.
I also learned something slightly annoying after further searching. I couldn't for the life of me figure out how to fold the seat back forward. Turns out before 75, they didn't fold.
That will tell you why it accelerates nicely.
I bet it is 235/75/15 or even 225/75/15
They are 235/75r15. Based on how much the speedo is off I'm guessing factory was the 225/75. I'm looking to go to 31s if I can find a deal on some wheels I like. 5x5 bolt pattern isn't all that common except for some Jeeps and a lot of those wheels don't look right on a C10. But I want to do 31s to fill out the fender openings.
Update on the truck. I'm driving it for work most days and I'm really enjoying it. Still liking the Street Demon carb. Since the install I've been playing with rods and jets to get it running better.
To begin with, the carb comes with primary and secondary jets stamped 80. The primaries also have the rods that effect the air/fuel mixture. The instructions recommend increasing a rod size for every 2000ft elevation above sea level. The largest rods you can get are 2 sizes larger than factory which is good for 4000ft. I live at 5000ft, so in order to get leaner on the primaries I had to drop the jet size as well. I ended up with 76 jets and the factory 5260 rods which was a little leaner than increasing 2 rod sizes with the 80 jets. Confusing I know.
Luckily I found this handy chart put together buy a fella on another forum. I like it because it gives you surface area for the different rod and jet combinations so you can more easily figure out what you're doing.
I ran the 76 jets with 5260 rods for a couple tanks. I was only getting 10mpg and I felt it could do better. I read a lot of opinions on the Street Demon coming from the factory on the rich side, especially for a stockish engine. I decided to try moving up 1 rod size to 5464. If you look on the chart below you can see some of my notes. Where I'm at now is circled in purple.
After that change, I'm getting 12mpg. I think there may still be room for improvement, but I don't want to go leaner until I have an air-fuel ratio gauge.
Before the rod and jet changes I was also getting a hesitation/stumble when the secondaries started to open. Adjusting the air door didn't help so I dropped the secondary jets from 80 to 78. After that and the primary jet/rod changes, I have gotten rid of that stumble.
It's a lot of fun to drive now. I will do some more tuning once I've landed on a tire size and I have an AFR gauge.
To begin with, the carb comes with primary and secondary jets stamped 80. The primaries also have the rods that effect the air/fuel mixture. The instructions recommend increasing a rod size for every 2000ft elevation above sea level. The largest rods you can get are 2 sizes larger than factory which is good for 4000ft. I live at 5000ft, so in order to get leaner on the primaries I had to drop the jet size as well. I ended up with 76 jets and the factory 5260 rods which was a little leaner than increasing 2 rod sizes with the 80 jets. Confusing I know.
Luckily I found this handy chart put together buy a fella on another forum. I like it because it gives you surface area for the different rod and jet combinations so you can more easily figure out what you're doing.
I ran the 76 jets with 5260 rods for a couple tanks. I was only getting 10mpg and I felt it could do better. I read a lot of opinions on the Street Demon coming from the factory on the rich side, especially for a stockish engine. I decided to try moving up 1 rod size to 5464. If you look on the chart below you can see some of my notes. Where I'm at now is circled in purple.
After that change, I'm getting 12mpg. I think there may still be room for improvement, but I don't want to go leaner until I have an air-fuel ratio gauge.
Before the rod and jet changes I was also getting a hesitation/stumble when the secondaries started to open. Adjusting the air door didn't help so I dropped the secondary jets from 80 to 78. After that and the primary jet/rod changes, I have gotten rid of that stumble.
It's a lot of fun to drive now. I will do some more tuning once I've landed on a tire size and I have an AFR gauge.
I'm not sure the temp gauge functions properly. If it is, it's not getting above 140ish. The heater puts out hot air, so I'm suspecting the gauge may be off.
I drive 60-65. I try not to get in the gas too much off the line, but it's also a lot of fun... And it is mixed driving, not straight highway. I'm running county roads to get Liam to school which means stopping every 5 miles or so. Then drive across Greeley from the northwest corner to the southeast corner.
I can tell the engine isn't fully warmed up until 15 to 20 minutes into the drive. I judge that by how well it "launches". Once it's fully warmed up there's no stumble off the line.
I'm driving Liam to his football weights at 5:30 in the morning so it's still pretty cold out. I'm also thinking that the adapter/spacer I used is keeping the carb from warming up as fast as the rest of the engine, especially on the cold mornings.
I drive 60-65. I try not to get in the gas too much off the line, but it's also a lot of fun... And it is mixed driving, not straight highway. I'm running county roads to get Liam to school which means stopping every 5 miles or so. Then drive across Greeley from the northwest corner to the southeast corner.
I can tell the engine isn't fully warmed up until 15 to 20 minutes into the drive. I judge that by how well it "launches". Once it's fully warmed up there's no stumble off the line.
I'm driving Liam to his football weights at 5:30 in the morning so it's still pretty cold out. I'm also thinking that the adapter/spacer I used is keeping the carb from warming up as fast as the rest of the engine, especially on the cold mornings.
When mine was mostly stock on little tires, it would get 12-14 like that if I stayed out of it. I'd get really decent on a long run on the highway, and it would average 14.5 at 75
Not sure how much difference you lose on the auto
Not sure how much difference you lose on the auto
It's your fault for recommending that muffler that I can't stay out of the pedal.
