Hot Rods Rochester 2gc on Flathead

I am switching out the 94's on my flathead with a single 2gc. Everything is together and seems to be running great but I'm thinking it is still a little rich. The Rochester is off a 64 Chevy 283 and the Flathead is a pretty much stock 59AB. The carb had #55 jets in it to start and was super rich so I swapped them for #52s. Still getting a puff of black smoke. I'm wondering if anybody else is running one on a stock flattie and if so where should I start with jetting? Looks like I can get them down to #45 or so. Trying to not buy all the different sizes and swap them all in.

 

I have a 2g on my 8ba. Running #52 jets I think.
Maybe look at your timing, compression, spark, etc?

 

2GC has 52’s on a stock 283’s with 9-1 compression in 1965. It’s the compression that determines the jet size. It’s air to fuel ratio and compression. If you have 8-1 I’d try a 50 first.

 

Does the jet number refer to the hole diameter or the area of the hole?
Bob

 

Running 1 on my 51 merc I have a 50 jet in it does fine,you may need to go one size smaller

 

I am running one with 52's on the '51 Merc in my '51 Ford. It seems to be right on.

One thing we haven't addressed here : What distributor are you running?

 

Crab distributor

 

The inside hole that allows fuel to flow

 

I picked up a new vacuum gauge to tune the carb. Got it running pretty damn good with the #52 jets in there. I'm still going to pick up some #50 to see what it does.

 

Depends on the jet

MOST Rochester jets will have a diameter in thousandths with that number stamped on the jet.
SOME Rochester jets will have the LAST TWO DIGITS OF THE PART NUMBER STAMPED ON THE JET.

The same is true for aftermarket jets.

And, just for the record, Carter, Holley, Stromberg, and Zenith all have their own conventions.

SUGGESTION: NEVER believe the number stamped on any jet. One never knows the origin, or if an enthusiast has drilled the jet oversize. MEASURE!

Jon.

 

This can happen. I spent 6 months chasing a problem on one of my cars until I checked the jets and found them to be seriously oversized. Never assume nothin'.

 

Well that is something I need to check. The 52 jets that I found were in an old carb off the shelf. I have some new ones that I'll throw in there to see if there's a difference.

 

Yesterday was a jet day. Started with 52s, went to 53s and then down to 50s. The flattie seems to like the 50s best in the garage but I'll have to get some miles on it to really see.

 

Since everybody likes pics....

 

Creative approach for the radiator support. Cool as hell.
Not enough room to run two of them, one on each side?

 

Just something different. I was going to split it and run two but thought the halo looked pretty cool.