Fixin to buy a low miles 96 E150 conversion van to travel and tow with. It's a roller 351W with mass air. Planning on building the roller up with a stroker kit, first choice is a 3.85 stroke kit with a comp ratio of 9.5 to 1. Gonna top it with iron GT40's (not the P's) leaving the stock cam but adding 1.7 Cobra's. Second kit is a 3.75 stroke but the comp ratio is only 8.62. Debating on replacing the iron manifolds with steel shorty's (not sure they fit with E150. You think the EFI will handle this ?

 

Yes the MAF EFI system should handle either of those, with the stock cam in there you'll see biggest gains at low to mid rpms which.. is probably exactly what you're going after anyway. Headers should also work, IIRC the frame rails are spaced a little wider in the vans so clearance should not be a problem, I don't know if the collector angles are different though.

 

As far as I recall the collector angles are the same on the vans. My old 95 was I know. Seems I recall though that the clearances to the engine cover though are tighter. You're right, I'm looking for more bottomend pulling, definately won't be a hotrod engine. I'm hoping it's got a 3.55 rear like my 95 van did. I'll see when we pick it up in a week or so. I've got a 97 roller 351 sitting on my engine stand, it'll get the rebuild then swapped into the van.

 

Personally I'd go with the higher compression combo. Not for displacement but because its always easier to lose compression then to gain it. Depending on head gasket compression thickness and actual combustion cc and actual deck height, compression that you calculate is usually the max you'll see.
With a stroker you'll really want to do headers of any type. The cast manifolds will smother a stroker within 3-3500 rpm probably.
The later stock roller cam is the best, but I think you may be able to get a custom one made for stock efi to work well. The stock cam is great for low end though, it's just my opinion that its designed and limited to 351cid and not 385-400 CID range.

 

I would really rather see a lower comp ratio than 9.5 to 1 for towing. I don't really want to give up the little extra torque difference, (if there is any in a difference in .15" stroke--3.75 vs 3.85) That level combined with the F4TE's zero overlap factors ups the octane requirements. I've run this cam in a couple of engines, one was a carbed Explorer motor and while it was fine on 87 most of the year, the summer months I had to switch to midgrade to quench the pinging. As far as it being easier to lower the ratio via head gaskets, that may be true for an engine sitting on a stand, but not after it's sitting in the vehicle, especially a van. Besides, I have one head gasket I trust on these engines..........that's the expanded graphite O.E gasket. I know they work, I'm not about to start experimenting with something else here. The cam specs are perfect for what I'm doing, regardless of the displacement, like I said, it's not going to be a hot rod engine, but a low rpm towing rig. It's specs are pretty much in line with any RV style cam you can find, run with 1.7 rockers. All I really wanted to make sure of was the Mass Air system being able to handle the extra cubes and the little extra head flow. As for headers, that's going to be limited by the dimensions of the engine cover of the E150. I too, would rather headers over manifolds, but I may not have a choice. I had a 95 E150 before with the 351, there wasn't much extra room in the box to work around, I've always been curious to know how they managed to wedge the Mod motors, 460's and the 7.3's in these things, unless they enlarged the box in those.

 

The combustion chamber design of the cylinder heads on these motors isn't that advanced so the motors are relatively detonation prone and sensitive to excess compression, the one exception to that rule was the much hated E6SE head. That head was cursed with terribly small and restrictive ports but the chamber design really did promote mixture swirl and this made a dramatic difference in detonation sensitivity. As an experiment some years ago I bought a set and spent considerable time porting them and then installed them on a 5.8. This motor was remarkable in it's ability to run without detonation in a heavy truck with quite a bit of ignition advance.. upwards of 16deg initial. I had my E7 headed 5.0 setup with the same ignition advance originally but it was pretty easy to induce heavy pinging when lugging the motor and it was completely useless with a heavy dump trailer attached so I had to back timing out to 12deg. Both of these motors had 9:1 static CR.

 

Well I'm going to polish the chambers and remove the sharp coners to mitigate this. If I can find a kit that's got both the lower ratio (8.6 vs 9.5) and the 3.85 stroke that's what I'll likely go with. Got some HP/TQ numbers for the 9.5/.3.85 stroke combo, 287HP/428 TQ. That's about equal to the old 390's, which I ran years ago, The GT390 I ran in a 70 F100 never lacked for pulling power in that truck with a C6 and 3.50 rear. The Explorer 5.0 I ran in my 89 Ranger was fine with 12* initial on 87 most of the year, 89 in summer with the same cam and ported/polished E7's with it's 9.0-9.5 to 1 ratio. You think I may need to upgrade the injectors ? Or will the stock ones do ?

 

I also prefer the oe gasket. I've had great luck with them. But unless you know their compressed thickness when calculating compression ratio, you may end up with a thicker gasket, or thinner.
The cam is the problem with detonation, that's why you change it for something better. Don't bandaid the problem or make excuses. The engine will be apart so invest the little extra money and replace it while engine is out.

 

300hp is no problem for a clean and healthy set of 19lb injectors, it's pushing the duty cycle at the top end but the reality is you're only gonna go there occosionally for a few seconds at a time. Upping the base fuel pressure a few pounds can mitigate that some too.

 

As far as the calculated ratio is concerned, a few thousandths either way doesn't really make any difference to speak of, especially with the increased displacement. As far as the cam goes, I might swap in an HO roller,(I have a couple of those in my box of cams) but nothing larger.

 

Then in this case I'll probably go one size bigger just to mitigate any future problems with dirty injectors later on. That and in the instance of climbing mountain grades, the full power will be used then and not just for short periods of time.

 

You can't just install larger injector and expect them to work correctly though, you have to tell the computer(tune it) or try to fool it with one of those "calibrated" MAF meters. IMO it's not worth the cost or hastle to do either of these as I don't think you're really gonna be stretching those 19s.

 

I always laugh and shake my head when someone says this.
I'm sorry to argue but stop justifying why an oem cam of any type will be fine on this engine. It's almost 100cid bigger than what the ho cam came in stock, which was a compromise for that displacement from factory as well due to emissions and such.
Spend the money on a correct cam for the engine. It's only a little more money to your build cost and I'm sure you'll be much happier.

 

Ok, give me some specs on what you think the specs should be. When you do, I'l show you some O.E. specs on a few engines of the same displacement and we can make a vaild comparison. (like the specs in your GT390)

 

My 390 isn't too special. It's made with a few used parts my engine guy saved over the years like arias pistons and lunati rods. Cobra jet heads race ported and bigger valves. He had a lead on an oem 425hp 427 cam that I persued and got from the old guy who bought it new. At the time I really wanted the old school parts, that was back when I was 20 years old and didn't have as much experience as I do now. I'd like to put a solid roller in now.

As far as your engine, your application, and your cam needs, I'm not an expert, I only point people in the right direction so they aren't disappointed in their choices later on.
You just said that the oem cam is prone to detonation, and then you say you will work around it by going with lower compression. The 5liter ho cam is an "upgrade" for most people, but compared to the crane and comp cams that conanski usually recommends, it's still not as good for the application you want to use it for.
I'm just saying that it would be in your best interest to get a cam for the application you are building the engine for.