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Want to switch to 4 barrell!

2K views 18 replies 9 participants last post by  Cougar Kitty 
#1 ·
My choke sticks on my original carburator. Always did! I've heard I'd be better on gas with a 4 barrell. Got to change the intake manifold too. What does everyone suggest? My mechanic says Edelbrock.('72 XR-7 351 Cleveland 2 barrell) :1zhelp:
 
#3 ·
If you switch it is best to put in a bigger cam. Without a different cam you won't necessarily get better performance, just more fuel. I don't know about fuel economy improvement. I've always been more concerned with passing cars than passing gas stations.
:wave:
 
#4 ·
A 4v and a less restrictive dual exhaust system will make a significant performance improvement on a 351C-2v and even improve gas mileage, if you can keep the secondaries closed.

But, you're right, a cam swap will make a larger difference. Still, I was very impressed with the difference in my car when I went with headers, dual exhaust and a 4v. Even before the cam swap, the car was MUCH stronger than stock.
 
#5 ·
If you want to go 4bbl by all means go ahead. It would be cheaper to fix your choke though. If you dont mind spending the money go ahead an go the 4 bbl route. Eldebrock makes a nice conversion mainifold and I recomend highly the eldebrock performer 600 carb to go with it. They come with a electric choke and you can get the auto trans kickdown lever like jim says.

Dont worry about changeing cams unless you want to, but I definalty suggest like Jim already mentioned a good free flowing dual exhaust if you dont already have it.

My buddies kid has the same manifold on his 73 stang and it really runs nice but he has the 600 holley and all of a sudden after setting the winter its blowing black all over the garage floor when idleing and I have to fix it for him soon. Go with the Eldebrock carb. mm
 
#6 ·
CARB

I was told I couldn't get just the choke part. I have to get the whole carburator!:mad:
 
#9 ·
Thanks everyone for your input!

How much to switch over the carb and the intake manifold? I also want to put an electronic ignition in. The car was overhauled 10,000 miles ago so, I don't want to put another cam in it. I want to keep it as stock as possible. I have no tools or know how to put this stuff in. I have to pay a mechanic. Oh, I do have Flowmasters on it. Sounds better than those 5.0 Mustangs!!:D
 
#10 ·
Summit Racing carries the manifold for around $160. Edelbrock and Holley carbs are both around $220. Figure another $40 for the 4v bracket (from Mustangs Unlimited), $5 - $10 for the kickdown extension rod and another $10 - $20 (depending on your taste) for intake manifold / valley pan gaskets.

I started out this way as my motor has less than 3K miles on it. I still ended up changing the cam :) Once you start modifying components, it's hard to go back and you can never have enough power :D
 
#11 ·
Run the 4bbl!

I say run the 4bbl! You have to be careful though, like jimk351c said, once you start... it's hard to stop. We have been rebuilding my cousins 289 and we planned to go real mild, next thing you know he had a hotter cam, headwork done, Performer manifold, and a Demon 750 w/vacum secondaries! And he's still not done...

I think you'd be happy with a nice manifold and a 600cfm carb. Doesn't sound like you want too much power out of your cat.
 
#12 ·
You're right b0nes421. My last Cougar needed an oil pan and new valve seals. Ended up replacing everything but the block, crank, and head castings! I would still put a bigger cam. You're already getting away from the stock look by changing the intake and carb. Plus it will make the exhaust sound even better. But since I'm not paying or volunteering to do the work it is just my $0.02.
:wave:
 
#14 ·
Switching a 351c to a 4 bbl

I have been considering the same, headers, intake manifold, and a 600 cfm but what about 4 barrell heads? Wouldn't swapping the 2v for the 4v heads be more efficient and provide more hp?
 
#15 ·
Without going into details, the 2v heads with a 4bbl make nice street engines. The 4 bbl heads have the potential for more hp but the ports and valves are so big you would lose some low end torque and around town driveablity.

I know some 4v owners will say its not that bad but if you just want to perk up your 2v the 2v heads are a nice way to go and a little 600 may help your mileage depending how you drive it.

Cougar Kitty, sounds like its time to buy some tools and a auto manual. Them mechanics get expensive in a hurry and the tools will pay for themselves in no time. mm
 
#17 ·
Hey I got the same plans on my end.. Summit has a carb and intake combo, price is about $383.00, but you can get the performer intake[ dual plane low end torque] or the weiand intake[single plane intake upper end HP]. If you make it happen in the near future keep us updated......Lance
 
#18 ·
Edsel!!

How are you? I found J+J Auto Body. I do work at Frisby Aerospace! Never been to Farmington Dragway...I would love to see you race your '68 Cougar. It looks really nice! Who is a good reasonable mechanic around here?:wave:
 
#19 ·
6t8cat

Wow! That's a good price! I need to look into that. Right now, my power steering hoses went and I can't seem to find any around. I have to have them made or at least one of them. It sucks because it is sooooo nice out and I want to drive my Cat!:(
 
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