93 ext cab short box engine swap

[mhau93obs]

So I just picked up a nice 4 bolt main 350. Missing the thermostat, carb, and distributor for 60. I made sure to check it out with a bore scope and pull off the valve covers. Everything looks beautiful and very well taken care of. The gentleman pulled it because of it burning/leaking oil and the only evidence I saw was a leak around the rear of the passenger valve cover. I guess now I'm looking for carburetor recommendations. Nothing really above 650cfm. I plan on running vacuum secondaries with gm hei distributor.

 

[Schurkey]

Why on Earth would you limit yourself to a "650" carb, when GM used 750s and 800s on these engines?

One word: Quadrajet.

Tuned properly, good for ~600 horsepower if the rest of the engine will support it.

Get the Cliff Ruggles, and the Doug Roe Q-jet books, and enjoy.

 

[mhau93obs]

650 cfm is what was recommended to me by the gentleman i picked it up from. Then again i never told him i planned on doing a complete reseal. So my best bet would be to just try and get my hands on an old roschester quadrajet either rebuilt or get one and rebuild it then? Also based off the casting numbers its an 80-85 truck engine. Not sure if that makes any difference, everything looks pretty stock to me, all in all its a really good condition long block. Since I'm going from v6-v8 i know i need new motor mounts, i found this kit, https://autofab.com/product/88-97-chevy-gmc-4x4-truck-with-350-v8-motor-mounts/ would these work for my needs? One final question is how hard will it be to convert it from the vbelt to serpentine? i have the whole serpentine setup off my 4.3, and from my understanding it should bolt right up to the block i picked up? I'm sorry for so many questions, I just want to make sure i do everything properly and not mess anything up. Luckily its still a good 4.3 so once i get the 350 in mine, the v6 is going into my buddy's s10 to replace the lethargic 2.2 4 banger.

 

[Sean Buick 76]

650 cfm is what was recommended to me by the gentleman i picked it up from. Then again i never told him i planned on doing a complete reseal. So my best bet would be to just try and get my hands on an old roschester quadrajet either rebuilt or get one and rebuild it then? Also based off the casting numbers its an 80-85 truck engine. Not sure if that makes any difference, everything looks pretty stock to me, all in all its a really good condition long block. Since I'm going from v6-v8 i know i need new motor mounts, i found this kit, https://autofab.com/product/88-97-chevy-gmc-4x4-truck-with-350-v8-motor-mounts/ would these work for my needs? One final question is how hard will it be to convert it from the vbelt to serpentine? i have the whole serpentine setup off my 4.3, and from my understanding it should bolt right up to the block i picked up? I'm sorry for so many questions, I just want to make sure i do everything properly and not mess anything up. Luckily its still a good 4.3 so once i get the 350 in mine, the v6 is going into my buddy's s10 to replace the lethargic 2.2 4 banger.

Perfect engine mount kit yes!

I agree I would use a Q jet if possible but here’s my advice. Contact this company, tell Mark that Sean Buick sent you and explain your engine combo. He will build you a custom Q jet to bolt on and enjoy. He’s setup a family shop with his son Tyler and his daughters as an assembly line of precise carb builders! I’ve known him for 20 years and he’s a great guy.

Quadrajet Power, Your One Stop Quadrajet Shop

Quadrajet service, parts, kits, restored originals

quadrajetpower.com

The Q jet in proper form is the best most precise carb available to this day. Smaller primaries For efficiency at low throttle and cruising and huge primaries when you drop the hammer! These carbs are CFM on demand, you can’t overcarb an engine when you use one. My old 88 4.3 astrovan had a 750 CFM Q jet and I’m sure it only swallowed 350 CFM as needed. Amazing carbs but dont dare let a shade tree mechanic touch one it will never be the same again. They are complicated, precise and amazing when built and set properly. I’ve got 4 on the shelf, all pro built my Mark or another guy I trust named “everyday performance”, he’s an engineer that does carbs as a hobby. Use the electric choke kit they both offer.

I only stopped using Q jets as I was adding turbo boost so the CSU Holley carbs became my go to.

 

[Sean Buick 76]

For Holley or edelbrock carb yes 650 max on a 350 unless it’s heavily modified. The holley is crude but easy to re-calibrate by anyone. The edelbrock is more user friendly and generic but will give up HP potential if that matters.

For drag cars, Holley all day.

For long distance drivers or daily drivers custom pro built Q jet.

For quick and easy plop on and run ok but not optimal edelbrock

 

[mhau93obs]

Perfect engine mount kit yes!

I agree I would use a Q jet if possible but here’s my advice. Contact this company, tell Mark that Sean Buick sent you and explain your engine combo. He will build you a custom Q jet to bolt on and enjoy. He’s setup a family shop with his son Tyler and his daughters as an assembly line of precise carb builders! I’ve known him for 20 years and he’s a great guy.

Quadrajet Power, Your One Stop Quadrajet Shop

Quadrajet service, parts, kits, restored originals

quadrajetpower.com

The Q jet in proper form is the best most precise carb available to this day. Smaller primaries For efficiency at low throttle and cruising and huge primaries when you drop the hammer! These carbs are CFM on demand, you can’t overcarb an engine when you use one. My old 88 4.3 astrovan had a 750 CFM Q jet and I’m sure it only swallowed 350 CFM as needed. Amazing carbs but dont dare let a shade tree mechanic touch one it will never be the same again. They are complicated, precise and amazing when built and set properly. I’ve got 4 on the shelf, all pro built my Mark or another guy I trust named “everyday performance”, he’s an engineer that does carbs as a hobby. Use the electric choke kit they both offer.

I only stopped using Q jets as I was adding turbo boost so the CSU Holley carbs became my go to.

Perfect, thank you so much. I will definitely look into what he has to offer. Until i get proper funds for a better carb I'm most likely going to go to my local pick a part and snag one off of there, not too sure quite yet though. As for the serpentine setup will mine bolt up to the 4 bolt block? Or will i have to get adapter kits? What do you reccomend for a distributor as well? What is a good thermostat to throw in?

 

[mhau93obs]

Ultimately my end goal is to have a daily driver with the occasional towing excursion for like camping or making a dump run.

 

[Sean Buick 76]

I haven’t done it yet but my plan is to run a 92 serpentine setup on my 80 4 bolt main turbocharged 350. Most of the accessory holes are in the heads so it shouldn’t be an issue but don’t quote me on it. I’m using 95 vortec heads so I don’t foresee an issue there. Using a GM marine 4 barrel carbed intake as well.

Run a HEI SBC distributor, preferably an original GM one not a $89 China copy. Look on your local classifieds and same for a carb. A junkyard carb is an unlikely win.

For the thermostat use a 180-185 version with a 1/8” hole drilled in the perimeter but inside the gasket sealing area.

 

[mhau93obs]

if i may ask why the 1/8" hole? I've never heard of that being done to a thermostat.

 

[Sean Buick 76]

I would consider using the TBI off a 350 of that era. Your trucks wiring is all there and functional, simply swap in a TBI 350 computer and build or buy a plate to adapt a stock TB onto the carbed intake. The easiest way to do it is to junkyard for a matching intake, throttle body, and heads and bolt that all onto your 4 bolt block.

The advantage of the TBI engine over all the modern stuff is simplicity and reliability.

Another factor is the year of your truck. Being a 93 you need to consider getting the 4L60E to be happy once the EFI is removed. You need a throttle position sensor, torque converter lockup control etc added to your setup and some other considerations.

Even though I’m a carb guy I’m only carbing my 92 as it has a manual trans. I wouldn’t bother with an auto truck.

The hole is to let trapped air out of the engine to make it easier to burp the air out. My failsafe method for cooling systems. Run the engine with the rad cap removed and keep adding coolant as needed. It will take a while but once the thermostat opens it will burp a bunch of coolant from the rad. Shut it off, top up the rad, add the rad cap, and fill the external resivoir to part way full and enjoy a system with no air pockets.