Carb
Lead Driver
Joined: Jun 2006
Posts: 5,669
Likes: 987
From: Near Yosemite CA
Welcome to FTE KPK, and 85e150 is correct, you're not going to gain much, if anything... best bet is to swap in a 300 and go with Offy DP 4bbl intake and FI exh manifolds.
Are you looking for more power or cool factor? I swapped the 240 in my 6 to a 300, same 1bbl carb/exh and really only noticed a bit more pep, same mileage at 18 avg, seemed to pull hills better, but, on my previous 66 F250, I went .030 over, new cam, Offy intake, holley 390cfm 4bbl and Hedman DO headers to 2" out and THAT was an animal, a 300 sixer in an old truck animal, but still had a growl!
Stock 240/300 I wouldn't go over 400cfm regardless of 2 or 4bbl, I put a Holley 390cfm on a friends jeep with a 350 cheb in it, it had a 650cfm 🤦♂️ mileage doubled as did drivability and wheeling, everyone over carburates engines thinking it's the cats meow for performance, it's not.
Are you looking for more power or cool factor? I swapped the 240 in my 6 to a 300, same 1bbl carb/exh and really only noticed a bit more pep, same mileage at 18 avg, seemed to pull hills better, but, on my previous 66 F250, I went .030 over, new cam, Offy intake, holley 390cfm 4bbl and Hedman DO headers to 2" out and THAT was an animal, a 300 sixer in an old truck animal, but still had a growl!
Stock 240/300 I wouldn't go over 400cfm regardless of 2 or 4bbl, I put a Holley 390cfm on a friends jeep with a 350 cheb in it, it had a 650cfm 🤦♂️ mileage doubled as did drivability and wheeling, everyone over carburates engines thinking it's the cats meow for performance, it's not.
Laughing Gas
Joined: May 2021
Posts: 1,163
Likes: 360
From: Anderson, California
I built-up a 300 gasser in 1996 for my '77 Ford F350 4x4 Crew.
It is punched .040 over with Hyper pistons approx 9:1 compression with Comp cam mid-range, Clifford intake and headers.
I am running a universal 600 Holley 4-bbl for Mid-Range rpm, and the rotating assembly was professionally balanced too.
The engine is no powerhouse, but I love the nostalgia of the prepped 300-six, and it runs great.
I can't remember what year block and head.
To get optimum performance, I tune the engine with a Vacuum Gauge.
Most off-the-shelf Holley 600's come stock with a 6.5 power valve, and I tossed it for a 9.5 power valve as the engine pulls 20-inches of vacuum at idle. Accel pump boosters can help eliminate low end stumble and hesitation.
In my '78 Ford Chateay club wagon, I'm running a balanced and preppped 429 which would be a good swap for you to perk up that pickup. LoL
It is punched .040 over with Hyper pistons approx 9:1 compression with Comp cam mid-range, Clifford intake and headers.
I am running a universal 600 Holley 4-bbl for Mid-Range rpm, and the rotating assembly was professionally balanced too.
The engine is no powerhouse, but I love the nostalgia of the prepped 300-six, and it runs great.
I can't remember what year block and head.
To get optimum performance, I tune the engine with a Vacuum Gauge.
Most off-the-shelf Holley 600's come stock with a 6.5 power valve, and I tossed it for a 9.5 power valve as the engine pulls 20-inches of vacuum at idle. Accel pump boosters can help eliminate low end stumble and hesitation.
In my '78 Ford Chateay club wagon, I'm running a balanced and preppped 429 which would be a good swap for you to perk up that pickup. LoL
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