It's a 16 ft box van. Way under powered. I can't even get it to 55 mph. Any suggestions?. Upgrade to a 5.0?. Can I boost it somehow.? It's in great shape. 4 speeed. But way to slow. And smokes a bit. And I'm on a very tight budget. Any help?

 

Forget about a 302! The 6 is a much better truck/van engine. I'm going to be swapping out a 351W in my 89E350 in favor of a modified 300 6.

Since you are working on a budget. It will be cheaper to just do some mods to your 6. Swapping to a V8 can start getting expensive real quick.

There are a lot of things you can do to really wake up the 300. They are extremely choked down in stock form. How well do you think a 302 would run with a 1V carb?

But first things first, make sure the engine is in good shape. No need to modify a worn out engine. What color is the smoke? White? Black? Blueish/gray? I would suggest doing a compression test and hook up a vacuum gauge to make sure you've got a good solid/healthy engine.

Here's some modifications I would recommend:

1. 87-96 300 ( 4.9L ) EFI dual exhaust manifolds. These are basically two cast iron shorty headers. These came stock on EFI 300's. They flow much better then the stock carbed exhaust manifold. These can be found for $25-$100 used or up to $200 for a new pair. Also go with a larger freer flowing exhaust system to take advantage of the freer flowing manifolds.

2. Swap to a Offenhauser C-series ( not the DP ) or Clifford Performance single 4V intake manifold. Then add or make a 4V to 2V adapter. The intakes will run between $100-$275 for a used one or $300-$400 new. Then run an Autolite 2100 or Motorcraft 2150 2V carb. These came on Ford V8's in the 60's ( Autolite ) & 70's ( Motorcraft ) . Go with one of these in either 1.01, 1.02 or 1.08 sizes. These will run $15-$100 used or $150+ for a reman'd one.

3. Swap out the rocker arms for some chevy 250 6 cylinder rocker arms. These are a higher ratio rocker arms. So that basically gives you more valve lift for a lot less money then a cam swap.

4. Swap camshafts. Pretty much all the major cam companies have camshafts for the 300. You want to go with a cam that has more lift and slightly higher duration then the stock cam. This starts getting into the major engine tear down here. And you will need the camshaft, lifters, valve springs and hardware.

5. Swap to a Ford 240 cylinder head. These heads have smaller combustion chambers then the 300. But otherwise they are the same as the 300 head. This will raise your compression ratio by about a .5. So if it starts at 8.5:1 it will bump it up to around 9.0:1. If you do get a different head some port & polish work will greatly help too. Especially in the bowl areas.

I'd start with #1-3. And if you ever need to tear into the engine then do #4&5.


Here's some pics of the set up I mentioned for your van.

 

Thank you for all the feed back. I'm in st. Charles m.o. right now if your close dude I'd love to show me first hand what you think. I wish my motor looked half as good as yours. If I found one out of say a 90's or so f series. How hard would it be to swap. Would you keep it carbed?

 

I'm up in Minnesota.

Is your van a step van( like a bread van/ UPS style van ) or a cube van ( Econoline front body with a big box on the back ) ?

Those pictures aren't my van. They belong to someone that use to be a member here.

I personally prefer carbed engines. They are simpler with less parts to fail.

Swapping to an EFI engine will require a lot more then just the engine.

If it was me I'd just keep the engine you've got and modify it. But it's your van so do whatever will make you happy.

 

Start by uncorking the motor, low restriction exhaust mods such as removing and/or replacing the cats and/or muffler/s and using bigger pipe would be good start..
Aside from that the next biggest improvement will come from changing the camshaft but i would start with the exhaust and see how far that will take you..
Box van is very heavy so perhaps a standard full size van without the box would be better choice..

 

Yeah. It's like a bread van.it's big

 

I've never dealt with a step van. So I don't know what kind of room you are working with around the engine. But if you are considering swapping in an EFI engine you are probably in for a lot of fabrication. None of the fuel lines, tanks, wiring, etc. from a truck will be the same. And the carbed engine has more power potential then the EFI 300's.