Well I suppose its time to participate a little here. I have two Ford six projects going at once. The 1960 Ranchero is on hold for a while and the '79 f150 swb is at the front of the line now.
Basically I have a truck with a sound 400 v-8, T-18, and NP205 t-case on 35" tires. I like it, but I would like it a whole lot better with a 300 I-6 and a 5 speed. I have all of the parts and the existing drivetrain comes out in the next few days.
I chose the Dodge NV4500 trans conversion for two reasons. The most significant is the fact that the ZF 5 spd. uses the infernal internal slave cylinder to actuate the clutch-the only thing that Ford ever did to to absolutely disgust me. I refuse to own one. 2nd reason is that I traded for the trans from a V-10 Dodge after doing my homework and found out how to use it instead of the V-8 version (proper parts selection). That is material for a different thread.
The heart of the matter here is the beloved six popper. My motor is a 95. I am ditching the EFI in favor of the Offy DP, small 4bbl (have an Eddy 500, working on getting a 4100 though), custom cam, and DS II ignition.
The cam is a Comp Extreme lobe grind with 249 adv (measured at .006) and 206 @.050 with .443 lift. The idea behind this is to have a lot less gross duration but a whole lot more at .050 where it actually will make power. The stock cam in the 300 is 268 adv./ 192@ .050 with .400 lift. I also went with 112 LSA instead of the stock 110. This equates to less fuel an vacuum squandered on valve overlap. The engine is being built around the concept of high vacuum producing snappy torque and acceleration along with efficient use of air and fuel.
Well, I tested the compression a few days ago on the six before yanking it from the donor truck and things were real good until #6. It produce 110 psi cold, far below what the others read. Testing hot revealed a reading of 75 psi. Oiling the cylinder once the motor cooled down gave the same numbers. Tight valve-time for valve job.
No big deal. I tore down the engine yesterday and much to my chagrin, #6 has a little ridge near the top and I can see a hint of marking where the rings sat for a period of inactivity due to moisture. Both are very minor, but bother the heck out of me.The other 5 cylinders still have cross hatch marks and are remarkably uniform for a 223,000 mile engine.
So now the big decisions. Which pistons do I go with to raise compression and do I jump up to 1.94/ 1.60 valve combo (which really isn't in the budget, but now is the time if its to be done)? The parts combo I am using is not intended for much revving, but will the valves gain me a little spunk without hurting my goals? I think of the 400, an engine that shares the same bore and stroke and how well it responds to removing the horrifically restrictive factory intake. It has Cleveland 2V ports, etc. The 300 is still choked with restrictive head ports and tiny valves. Any thoughts?
Pistons are the real kicker. Before anyone spouts off "do the math" I would like to point out that the manufacturers seem to do one heck of a good job keeping piston dish volume a dark secret! Considering the 360 piston option since they are flat top with a comp. height of 1.759 and pin dia. of .9751. The pistons in my 95 block have a comp. height of 1.781 (to the best of my ability to measure-within a few thousandths) and matching pin dia. I am not too concerned about successive rebuilds since I only put about 5000 miles a year on a full size truck. My other top option is to go with dished pistons that the manufacturer claims at 8.5:1 (I believe with 78cc combustion chambered head), measure the alleged 68 cc EFI head to find the real volume and then mill the head to end up at about 9.5:1. Thoughts? Anyone done the 360 piston routine? I know one of the moderators has.

 

I should add that most of my driving is above 5000' elevation, so compression should be my friend.

 

Personally I can't see boring a block to 0.050" or 0.060" over just to use a certain piston. Unless the block is already bored to 0.040" over. My first choice would to bush the rods down to .912" and use some 351W pistons. Or pick up a set of 65-67 300 rods then they will already be the correct piston pin diameter for the 351W pistons and are a stronger rod.


And you want the piston to be as close to zero decked as possible. And zero decked with a flat top is going to be too high of compression. Go with a piston with a compression height that will work for zero decking and a dish big enough to get your compression low enough to run pump gas.

I have measured the dish on the efi pistons, but I'm not going to post it. Because I'll never hear the end of it if I'm not remembering it correctly.

If you are planning to modify the head dump the efi head. The valve shrouding is bad enough with the stock sized valves. Go with a carbed 300 head or a 240 head. The little bit you'll loose from dumping the fast burn chambers is more then made up by the additional flow from larger valves and some port work on the carbed heads.

And if you cc'd your efi combustion chambers post up the #'s. So if I was wrong the correct #'s can be confirmed.

 

I have actually decided to go with the 360 pistons since I will lose quite a bit of compression opening up the chambers on my EFI head to unshroud the valves. I will likely end up with somewhere around 78 cc chambers. Here comes the measuring plate and syringe (if I can remember where I stored them!). The EFI head is reputed to actually flow a little better even with the valve shrouding issue. Still have not decided if larger valves will benefit me at all considering the working rpm range of the truck 95% of the time.

 

Not in an EFI head.

And I'd like to see proof that the efi head out flows the carbed heads. Especially if the carbed head has larger valves and port work.

 

I am just going by stock vs. stock. It is looking fairly unlikely that I will be adding the larger valves since the engine is not going to spend much time above 3000 rpm. It is also not that big a deal to add a carb head with big valves later if my needs change.

 

I seriously doubt there is much of any flow difference in the efi vs. carb heads in stock form. If there is a difference it would be pretty small. I think the biggest flow difference would be the manifolds.

The larger valves would help through out the entire rpm range. Just not in the efi head with out some major chamber reshaping. And the same goes for port work. And it's not just rpm's that's a consideration when you are talking head work. It's also valve lift. Anything you can do to increase the flow #'s is going to help even on a low rpm engine.

I'm going to be swapping a 300 into a Extended E350 van that will probably weigh in close to 8,000 pounds. I'm going with a 240 head and am going to port the head and go larger valves. And that van will be hauling heavy loads and towing one of my 20 foot car trailers.

If your plan is going to work for you then stick with it. That's what makes this hobby fun, there is no one single right way to do things.

 

The chambers are certainly getting reshaped. I guess it boils down to spending now or spending later when cash is a little less scarce. The other parts hanging behind the engine have gobbled up some of the budget. The good thing about an I-6 is that a head swap down the road is not too difficult.

 

I know how that goes! Just be glad you don't have multiple projects going at the same time. The more projects the less that gets done on all of them.

On my van I'm going with the NP435/NP205 combo. They are cheap and very reliable. I'm going to swap those in now and then later when the funds become available I'm going to add a Advance Adapters Ranger OD unit. It's not cheap but I like them and I'll just need to have the driveshaft shortened when I do install it.

Good luck with your build. And post up some pictures of your truck and your progress on it. We love pictures!!

 

Post pics of your van too! np205 suggests it's going to be a 4x4 one!

 

I've got more pictures of my van posted over in the van forum. It's a crusty bucket right now. Not a whole lot to look at. I'm going to be doing a full bumper to bumper rebuild on it. Along with a bunch of upgrades ( rear disc brakes, cargo van rear springs, Autometer Sport Comp gauges, etc. ) .





Maybe someday on the 4x4 part. The transfercase is mainly to get another low range. I do some fairly heavy hauling/towing and the low range of the transfercase comes in real handy if I'm backing a trailer up a hilly driveway. Or to compound the grany low just in case I need to tow a loaded semi truck or move a mountain.

 

I actually do have two going at once. The 1960 Ranchero is on hold until spring now. I will finish the stainless flooring at my leisure and call it good. The mechanical work on the half ton will be done in a relatively short time and then both vehicles will get paint when the weather warms back up next year.

 

Sounds like you are way better at juggling multiple project vehicles then I am. I've got 3 of my own and then I stuck repairing vehicles for family and friends too.

And it sounds like you've got some cool projects going. Good luck on them and keep us posted on your 79!!! The Ranchero too if it has an inline.

 

170 inline with some interesting changes, but that is for later!

 

Cool!