351M 2BBL or 4BBL?

[Jkuzie]

Hi Everyone! Pretty standard questions. I've been looking at going to a Holley Sniper on my pretty stock 351M. It's been bored .050" over and has a moderate cam in it, but nothing special. It currently has the standard 2BBL carb. Any benefits to going with a 4BBL Sniper or just sticking with the 2BBL? Thanks in advance!

[Joey.S]

Hi. I would go 4BBL on that engine if it was mine. Joey.S

[Jkuzie]

Any particular reason?

[GPatrick]

What's the application? Low RPM truck or a light fun car? A good 4-barrel intake manifold will be better than a factory 2-barrel, lighter than a factory cast iron, better distribution cylinder-to-cylinder (in most cases), but most of the benefits will be in the upper RPM range. For a truck the 2-barrel will probably be fine. For a Mustang, you'll probably have more fun with the 4-barrel if you have upgraded exhaust, etc. Tell us what you want to do and we can go from there. There have been a number of 289 powered Fords that have kept the 2-barrel and the owners seem to be pretty happy with their results. If a 2-barrel will work for you, you'd have more money for a nice new or modified fuel tank with an in-tank pump and a distributor that the Sniper can control since you wouldn't need a new intake manifold. If you go 4-barrel, skip the factory manifolds and go with a newer aluminum intake manifold.

[Jkuzie]

It's a '78 Ford truck daily driver about 50 miles round trip. Up north in Minnesota. Sometimes pulls a boat. Has headers and true dual exhaust. Your occasional drive through the timber.

[GPatrick]

I ran a four barrel on my 1970 F-250 with a 390 and it did pretty well. But for your use you can probably get away with the 2-barrel. You aren't going to be pushing the HP/injector limits. It supports 350 HP and I suspect you're below that. You'll want to get a 1/2" or 1" spacer to keep the Sniper somewhat isolated from the heat. You will not regret doing an in-tank conversion rather than the external pump that comes with the kits. I installed mine in the original factory frame mounted tank on my '70 and haven't had any pump problems.

You can get the system running with your current distributor, but you may want to upgrade to Sniper controlled timing in the future.

[andrewb70]

It's a '78 Ford truck daily driver about 50 miles round trip. Up north in Minnesota. Sometimes pulls a boat. Has headers and true dual exhaust. Your occasional drive through the timber.

I would do the 2 barrel. Andrew

[Danny Cabral]

Yeah 2BBL, since the engine isn't a high performance application.

[a b c]

If you want to intentionally restrict that engine, then go with the 2-barrel.

[Danny Cabral]

The 351M cylinder heads don't flow much air.

[Jkuzie]

Anyone have experience with a 2BBL Sniper on a 351M or 400?