2 brl carb and hopping up engine

[Don Coatney]

James;

Can you post pictures of how you did this?

[james curl]

Don, I used the same Chevrolet valves that you used. As you can see in your picture the edges of the valves stand proud of the block surface. The Plymouth valves that were in my engine were crowned and the edges were almost flush with the block surface. The valves contact the head in the front around to the outside of the combustion cylinder. As you look at your picture of the head you will see that the combustion chamber is crowned to the sparkplug opening. I used a round ended rotary file in my die grinder to remove metal from the upper head surface from the center around to the outside edge of the chamber above the two valves. I think that .090 is too much to have milled off if you are not going to have to rework the combustion chamber. I feel that the work was not worth the effort because after all the work the compression ratio is probably not any higher than the .070 mill.

[James_Douglas]

Lou,

The only way to get a specific CR and know it is correct is by using the dreaded math.

Get a 6x6 1/4 thick sheet of Plexiglas and drill a 1/8 hole in it. Use a rose to bevel the hole on the top side to help prevent meniscus from forming when dropping liquid in. Get a graduated cylinder with burette.

Have the shop build the bottom end. Then, have them tell you exactly what the CC is of the cylinder to the top of the deck. On my engine the piston was 0.0 meaning that it was flush with the deck at TDC. When it was all said and done my engine came out at just a little below 8.0 to 1.

Now take your head and set it on your bench. Put a little bit of Vaseline around the chamber and put down the Plexiglas with the hole at the very edge of the chamber. Slowly, and I do mean slowly, fill the chamber (use a cut off sparkplug in the sparkplug hole) with fluid. I use water with a few drops of blue ink in it. When you are done you can read off the burette how much CC went into the cylinder.

Then you just do the math. Then you have the shop mill it again. Then you measure it again. You keep going until you hit the CR you want. I did about 4 iterations.

Based on the milling chart and a couple of conversations with Don C, I figure that for approximately every 0.0034 milled from the head you get a drop of one CC. BUT, remember that the cylinder is not a perfect equal shape so that number will not hold up as you mill down.

I think you need a head CC of something like 85 with a gasket (felpro 7256) having about 18 CC for a total of 103 or so for a final CR of 8.0.

The best way is to get a sheet of paper out and measure it as the heads do have slightly different shapes and depths from the foundry.

Best, James

[Don Coatney]

Thanks James;

Excellent report!

[48mirage]

Lou,

This is kind of dated but a '56 Coronet had the Stromberg WW3-124. I've looked around but haven't seen one yet. I've also read 1 place that this was the same carb used on a '55 D56.

Jim

[Guest mikeys toy]

Based on the linkage showing it looks like it may have been mounted as the front carb in a dual set up. Can you post another pic from a little further back.

I believe the carb shown is a Holley Weber. These were used on a lot of late 70's small cars like the Ford Pinto, Mercury Capri, V6 Mustangs. etc. They were made under liscence by Holley for Ford Motors, and Carter for MOPAR small cars.Don't know the glow rate on these, but I believe they have adjustable or easily changes jets and metering rods. The v6's they were used on were in the 2.5 to 3 litre range so a single one may be a little small for the 3.7 (218) or 3.8 (230)

no, it's not; i have no idea what it is, but it's not a weber

the pinto's used the motorcraft (holley) version of the weber dfv, a little small for these old flatheads

a weber dgav would be perfect for them; a lot of "jeepers" are using them these days as you get great mileage and power when you want it. You can find them on ebay by typing in "weber dgav" or weber dgv (man. choke) or "weber dfav" or weber dfv Man. choke