Small Block Carb and intake ?

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Fishthatkills

Fishthatkills

Fish that kills
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I am gathering parts for my 67 273. I have an original 4 barrel intake and I am pretty sure I will get a Edelbrock 500 or 600 cfm to go with it. My question is this. Will the edelbrock need a spacer plate between the intake and carb for butterfly clearance? I am going from a two barrel BBD to the 4 barrel set up. My VIN number indicates the car came with a four barrel and was the HO commando. What increase if any can I expect with a four barrel. I have stock manifolds and true dual 2.5 exhaust with crossover and Magnaflow muffs.


John B.
 
Don't think you'll need any spacer. The carb that originally came on the factory 273 commando motors was a Carter which is the same as the Edelbrock. As long as you get a square bore carb you should be okay.

Back in the day when I rebuilt my 273 2 barrel & added a cam & 4 barrel Carter carb with a stock 273 Commando manifold & slightly domed pistons I could definitely feel the difference. Don't know how much was due to the cam & compression boost. The car already had a set of duals. When I added headers to this combo it REALLY woke up the car.
 
Edelbrock fits fine on the factory 4 barrel, no spacer required. Good increase in power and drivability. Could be better with bigger cam and valve springs to match, but not required. Enjoy!!
 
No problem with using just a gasket between the carb and the intake. The original 273 HP used a 625 cfm Carter 3855S, for what that's worth to you.

I hate to be a party pooper, but I'm a bit suspicious. My suspicion is that you have something other than the HP engine in the car, regardless of what the VIN says. It makes no sense to me to put a 2 bbl on a high compression engine. Also, if your avatar is of your engine, the finned applique valve covers that came on the 273 HP cars are gone. At the very least, some monkey business has occurred as the two most visibile identifiers of the HP engine are not present.

The factory HP cam had .425 inch lift. If it's an HP motor, you should get that kind of movement at the lifter or push rod. The other way to tell, as 64Cuda says, is to look for the domed pistons. If you have or can find someone with a lighted borescope to get in through a sparkplug hole, you'll be able to tell without popping the heads. The piston will be either flat or domed, if they are original pistons. The whole package of cam, carb, and compression boosted the 273 from 180 to 235 horsepower (gross, at least in 65 & 66.).
 
Yes I agree, The motor was replaced I suspect. I don't believe it to be a H.O. either. I have "felt" with a wooden stick and dont think the pistons are domed. However the VIN is correct and I am not trying to fool anyone! I want to increase the output of what I have. I have done extensive research on this car and I am very aware of whats supposed to be there and what is not. Unfortunatly the Previous owners are dead and I cannot confirm what was done to the car in the past. I do know a ring job was done at 75k (on this motor or the original motor is the question) and the car has about 110k on it.

I am slowly gathering parts as I go along, I plan on a 318 build bored .030 over this year and will take what parts I can use from the 273 and use them on the build. Hence the 4 barrel intake and carb combo question.

No party poop to it it's all in fun!
 
2 Darts said:
No problem with using just a gasket between the carb and the intake. The original 273 HP used a 625 cfm Carter 3855S, for what that's worth to you.

I hate to be a party pooper, but I'm a bit suspicious. My suspicion is that you have something other than the HP engine in the car, regardless of what the VIN says. It makes no sense to me to put a 2 bbl on a high compression engine. Also, if your avatar is of your engine, the finned applique valve covers that came on the 273 HP cars are gone. At the very least, some monkey business has occurred as the two most visibile identifiers of the HP engine are not present.

The factory HP cam had .425 inch lift. If it's an HP motor, you should get that kind of movement at the lifter or push rod. The other way to tell, as 64Cuda says, is to look for the domed pistons. If you have or can find someone with a lighted borescope to get in through a sparkplug hole, you'll be able to tell without popping the heads. The piston will be either flat or domed, if they are original pistons. The whole package of cam, carb, and compression boosted the 273 from 180 to 235 horsepower (gross, at least in 65 & 66.).
Click to expand...

The Commando motor also had a cast iron or steel (not sure which it is) Prest-O-Lite dual point distributor. At least, I know the 65 models had it. I've got one I took off of a 65 Commando motor.
 
All Commando engines had the Prestolite cast iron, dual point distributor. 1965-1967 manual or auto.
 
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