Phenolic spacer for stock 402?

[Sicklajoie]

Hello all,
I have problems with my truck cutting out under a heavy load on warm days after gassing up or if I've been sitting at a drive-thru or a stop light for extended periods of time.
I'm wondering if a carb spacer would do the trick.
I have a stock 402 with headers and a stock Rochester Quadrajet carb.
If anyone has any recommendations on what brand you've used and any additional modifications that are necessary after installation I would greatly appreciate it.
Thanks!

[LockDoc]

Originally Posted by Sicklajoie

Hello all,
I have problems with my truck cutting out under a heavy load on warm days after gassing up or if I've been sitting at a drive-thru or a stop light for extended periods of time.
I'm wondering if a carb spacer would do the trick.
I have a stock 402 with headers and a stock Rochester Quadrajet carb.
If anyone has any recommendations on what brand you've used and any additional modifications that are necessary after installation I would greatly appreciate it.
Thanks!

I put one on my White '67 with a 454 engine with a Quadrajet after experiencing the very same problems you now have. It was a 1/2" or 5/8" Phenolic that I bought from Summit. It also helped with the hard starting after sitting for a while when warmed up.
.

[Steeveedee]

Heating at idle is lack of air flow. Heating on the highway is from lack of water flow. My truck used to never start for about half an hour or so after being shut off; that went on for years, before I got it. If your radiator is clean, and your fan is properly coupled to the shroud, and the fan clutch is good, you might look into a high flow thermostat. It took me awhile to get it ironed out. I don't have a phenolic spacer. How hot does you truck run? My fan was not properly coupled to the shroud; I made a new shroud from aluminum that couples the fan properly. It still ran hot until I replaced the thermostat.

[Sicklajoie]

Originally Posted by Steeveedee

Heating at idle is lack of air flow. Heating on the highway is from lack of water flow. My truck used to never start for about half an hour or so after being shut off; that went on for years, before I got it. If your radiator is clean, and your fan is properly coupled to the shroud, and the fan clutch is good, you might look into a high flow thermostat. It took me awhile to get it ironed out. I don't have a phenolic spacer. How hot does you truck run? My fan was not properly coupled to the shroud; I made a new shroud from aluminum that couples the fan properly. It still ran hot until I replaced the thermostat.

Engine temp is fine, runs about 180 on a warm day with a 160 hi-flow thermostat. I rely on an infared gun instead of the temp gauge and the t-stat housing runs about 170-180 when I point the gun at it.

[Steeveedee]

Originally Posted by Sicklajoie

Engine temp is fine, runs about 180 on a warm day with a 160 hi-flow thermostat. I rely on an infared gun instead of the temp gauge and the t-stat housing runs about 170-180 when I point the gun at it.

I have nothing more to recommend. I do hope that when you find the solution, you will let us all know. I chased my tail for a bit. If you buy a phenolic block, make certain that that thing is flat before putting it on. I had a 305 SBC that I put an Edelbrock carb on. Had heat soak problems and put the Edelbrock phenolic spacer on it, but it leaked vacuum like a sieve. I sealed it up with Form-A-Gasket (we used to use a similar substance to seal vacuum leaks on the main condensers under the turbines, in the Navy), but I'll never use one of those spacers again. Edelbrock was worse than useless about it; they never even replied, when I complained.

[SRU1436]

I used the summit brand for a Holley on my Chevelle. Works good with no issues.

[yuccales]

Originally Posted by LockDoc

I put one on my White '67 with a 454 engine with a Quadrajet after experiencing the very same problems you now have. It was a 1/2" or 5/8" Phenolic that I bought from Summit. It also helped with the hard starting after sitting for a while when warmed up.
.

Been running this 1" from Summit for years. Solved the long cranking on a hot engine.

[Getter-Done]

I had similar issues.

What resolved mine was changing the 160 degree thermostat out for a 195 high flow thermostat.

It not only help with the carburetor loading up, it help maintain a steady temperature.

[Sicklajoie]

Originally Posted by Getter-Done

I had similar issues.

What resolved mine was changing the 160 degree thermostat out for a 195 high flow thermostat.

It not only help with the carburetor loading up, it help maintain a steady temperature.

I'm going to switch out the 160 stat for a 180 and drill a hole in it.

[Getter-Done]

Originally Posted by Sicklajoie

I'm going to switch out the 160 stat for a 180 and drill a hole in it.

Great Idea that will take care of the flow..

I have forgotten this trick.

The Machinist in me cannot help but suggest.: lol:

I would take a Twist drill several sizes bigger and Deburr the front and back side of the hole drilled.

This can be done by just hold the Twist drill in your hand.

I hope this works.

I have been down this road and it is satisfying when you find the issue with your particular issue.

[c30]

My 77 k10 400 small block was having severe vapor lock issues when I first bought it.
On a hot day, it would not restart for about a half hour after shutting it down.
I was thinking through all the remedies until one guy suggested that my mechanical fuel pump was tired. He was stating all the various problems caused by a weak pump.
These include some of the problems that you are having.
I put a new pump in it and all my problems went away.

[Sicklajoie]

Originally Posted by c30

My 77 k10 400 small block was having severe vapor lock issues when I first bought it.
On a hot day, it would not restart for about a half hour after shutting it down.
I was thinking through all the remedies until one guy suggested that my mechanical fuel pump was tired. He was stating all the various problems caused by a weak pump.
These include some of the problems that you are having.
I put a new pump in it and all my problems went away.

Thanks.
I'm covering all my bases and getting a new Carter fuel pump also.
Thanks to everyone that's responded with help and additional suggestions, much appreciated!

[Mike C]

The OEM big block air cleaner sits just under the cowl, and a spacer may or may not cause it to not fit. If it does, great, if not consider the GM style heat shield with the thick gasket and aluminum plate. Here is a link to one at TopFlight, they were just the first one i saw.

https://www.topflightautomotive.com/...iABEgKNsfD_BwE

[Sicklajoie]

Originally Posted by Mike C

The OEM big block air cleaner sits just under the cowl, and a spacer may or may not cause it to not fit. If it does, great, if not consider the GM style heat shield with the thick gasket and aluminum plate. Here is a link to one at TopFlight, they were just the first one i saw.

https://www.topflightautomotive.com/...iABEgKNsfD_BwE

Great thanks!

[1970cstblazer]

Are you running 10% ethanol blend fuel or straight gasoline?

[Rust_never_sleeps]

Originally Posted by Mike C

The OEM big block air cleaner sits just under the cowl, and a spacer may or may not cause it to not fit. If it does, great, if not consider the GM style heat shield with the thick gasket and aluminum plate. Here is a link to one at TopFlight, they were just the first one i saw.

https://www.topflightautomotive.com/...iABEgKNsfD_BwE

I had one of these on my 350. Not photogenic, but it worked fine.
My neighbor convinced me it wasn't original, and for some reason that bothered me at the time ;-)