I have a chance to buy a nice 428 crank for the rebuild of my 360. I've heard before that dropping a 428 crank (3.98" stroke) into an FE works, and was done by Ford briefly in the Mercury 410 engine. Anyone have experience doing this? Good idea or should I just stick with a 390 crank?

My biggest concern right now is compression ratio. My calculations (assuming 70 cc combustion chamber, flat top pistons, .030 overbore, .040 gasket height, zero deck) show a compression ratio of 10.9:1. That seems awful high for an FE, and I don't want to have to run premium in it. Am I calculating correctly? What changes would be best to reduce the compression ratio (dished pistons?), and what ratio should I be aiming for. This is going to be a tow vehicle, not a drag racer. It will have Edelbrock intake, stock heads, and tri-y headers.

Also, if I do use a 428 crank, what rods should I use?

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

Well, I think I just answered my own question, at least as to compression ratio. According to one of my references, factory spec for the deck height is 0.104. Although that seems awfully high to me, that would result in a compression ratio of 8.5:1 with a .030 overbore, 3.98" throw, 70 cc chamber, and .040 gasket. Now it seems a little on the low side. Would decking the block by .05 (resulting in a .054 clearance) to increase compression to 9.5:1 make sense, or would that just require premium fuel without significant power/torque gains?

Also, I'm confused about the internal vs. external balance issue. If adding a 428 crank, what other parts do I need to replace and how do I make sure the engine ends up in balance?

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

Oops. Neglected the fact that that .104" deck clearance on a 360 would be reduced with the longer crank throw. Assuming 6.488" rods and the shortest FE pistons (390 pistons with a compression height of 1.680", according to my references), that leaves a deck clearance of 0.012" and yields a compression ratio of 10.5:1. It's looking too high, again. I'd need 9 cc total dished out of each piston or machined out of each combustion chamber to get the ratio down to 9.5:1, right?

HELP!

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

I have heard that many pistons can be milled, the 428 in particular. That route is cheaper than custom pistons.
Eric

 

...too technical for this ole boy...

As for the 428 crank balancing, you just need to add proper weighting to the flexplate/flywheel. Your machine shop can do this for $100-$200.

 

Use the 428 crank, rods from anything 390 or bigger, get pistons such as what NAPA sells (cast around 10:1 and about $120, and I think the number is sterling 381P) and have them slightly dished, you want to keep the smallest deck height possible, or you want the piston as close to the top of the cylinder as you can get it.

 

That's what I did when making my Dad's 360 into a 410. I used a lathe and dished the pistons. Almost as deep as the valve eye brows and about 3 or 3 1/2 inches in diameter if I recall correctly.

I also cleaned up the combustion chambers around the valves which had to lower the compression ratio. I been looking for my notes with the exact details but haven't been able to find them.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 LWB 4x2, XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 4x2, 3.0, 5 speed, 3.73 posi

 

I did this to my 360. I found the 428 crank but already bought the L2291F pistons for a 390. I had them measured at the smallest point on the top and they were thicker than 1/2" so I had them cut to fit and ended up with zero-deck.

Use the 390 rods with ARP bolts and get a 428 flywheel and have it balanced. Most shops charge about $200 for balancing and it is a must.

I'm using C7AE-A heads that came stock with 74cc, I unshrouded the valve area and polished them smooth and ended up with 80.5cc
Don't remove material in the combustion chamber where it's flat against the piston as this will ruin the squish effect that's so important.

My cold cranking psi is 210 which is higher than I wanted but seems to be working well. There are some tricks to running reg gas on higher CR engines, block off the exhaust crossover and run cold air to the carb from in front of the rad and get a plastic or wood carb spacer. You can play with the timming and spark plug heat range too.

I did notice that this engine gets warmed up REAL fast, I've got the Edelbrock alum water pump, 160 high flow thermostat, 4 row rad, overdriver A/C type pullies and I port matched the water passage in the heads to the intake for better flow.

 

Well. I went ahead and bought the 428 crank and matched rods. I think I got a deal at $275 for the set, seeing as 428 cranks alone are going for $400+ on Ebay. The crank has been turned .010/.010, but as I understand it that isn't a problem.

I don't have pistons yet, but that will have to wait. If I use pistons with a compression height of 1.687 (the Ford spec for 410 pistons), I should end up with a deck clearance of .005. Is it really worth having the block decked .005 to get a "zero" deck clearance? According to "How to Rebuild Ford Big-Block Engines" by Steve Christ, the FE should not be decked unless it is so badly warped that the heads won't seal properly. My machinist also told me that decking the block will add expense because the intake manifold will have to be modified to fit right on a decked block. Plus, I really don't want to get the compression too high, and at .005 with .040 of gasket and 70 cc of combustion chamber volume, I'm already looking at 10.7:1. I figure that I can get that down to 9.5:1 with 10 cc taken out of the tops of the pistons and/or the combustion chambers. Decking the block .005 just increases the amount I need to remove elsewhere.

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

your only concern should be making sure that there is less than .050 clearance between the top of the piston and the bottom of the cylinder head. you should have .045 ( .040 gasket and .005 below deck) which would be fine, but also remember that most pistons now are made slightly shorter to accomodate blocks that have already been decked. If you only take a small amount off the block you shouldn't have to mill the intake.

 

KSD, the zero deck is an ideal thing to have, but if you are within 005 of that I would call it good enough. With 040 thick gaskets your quench pads will do just fine. You have a much bigger problem however. Either your machinist is unethical or incompetant. You NEVER mill an intake manifold. A light 005 cut wouldn't require any addition cutting on anything. Even if you were cutting 060 off the decks of the heads or block, the matching cut of 060 is made on the intake face of the cylinder heads, not the intake manifold. One also never cuts the bottom of an intake. If more room is needed you should be milling the top of the block where it meets the intake. Even with heavily milled blocks and heads, I have always used a bead of silicone in place of the manifold end seals and had no problems. Do you trust this fellow with you engine ? Has he or have you addressed the oiling needs of the FE series ? DF

 

428 cranks go for $302 bucks at. http://www.precisionengine.com/site/crank_kits2.htm
I don't know anymore about the business.

 

5 below sounds ok. I'd clean up the chambers first then measure them and calculate the CR after that. Like I said before, I got mine to 80.5cc with polishing and some other work. I think I'd do that before the piston work because I think cutting down the top of the pistons effect the squishing some.

It's best to deal with the blocking off of the exhaust cross over now because you'll really need a cool intake to help deal with the CR and pinging.

Sounds like an awsome deal on the crank and rods! Don't forget about the external balancing and oiling mods.

 

My mistake, not his. I misspoke. He was talking about milling the heads, not the intake. His point, though, was that the intake would not fit correctly without milling the heads if I had the block decked.

I'm not planning to deck the block. .005" of piston-to-deck clearance is as close as I want to get. I'm still concerned about high compression, though. I had a slight math error earlier that my machinist corrected for me. With 80 cc of total volume in the combustion chamber and piston valve relief, I'll have a compression ratio of 10.5:1 (using stock 410 pistons with a 1.687" compression height). To get that down to 9.5:1 I need to take another 10 cc out of the combustion chamber or piston. He doesn't think going above 80 cc of combustion chamber volume is realistic or advisable, and dishing the pistons 10 cc each has its own drawbacks. His experience, of course, is in building racing motors, so he doesn't see anything wrong with 10.5:1 compression. My problem is I don't want to have to run premium fuel.

So that's what I need to know -- should I live with 10.5:1 compression? How likely is it that I will have to run premium fuel? What's a reasonable compression ratio for 87 octane fuel? This thing is going to be a gas hog, so the extra 20% for hi-test is something I don't want to pay.

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

Anyone know anything about Sterling 390 truck pistons? They are Summit Racing part number STL-381P30 in .030 oversize. From what I gather, they are intended for 391 FT engines, but they are described as having a 1.660" compression height and a .097" dish. The low compression height combined with the dish should give me a compression ration of around 9.5:1 without any further modifications, and they're only $11 each. That sure beats a set of custom pistons for $500+. My piston/deck clearance would be up to 0.032", which ain't exactly zero deck but is still much better than the .104" that is stock on my 360.

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.