I sat down with the machine shop guy yesterday afternoon to discuss my 400's long block build plan, and am more confused than ever. I sourced the Badger flat tops for my build, and now they are telling me they would reccomend factory compression or dishing the flat tops to reduce it. The owner is saying the 400 does not like high compression, espeically for towing. I mentioned polishing the combustion chamber to help, doesn't that open it up a tad and help with detonation anyway? These guys are really good builders, highly reccommended and they have done quite a few 400's.

What is a good combo for the Badgers as far as head work goes to keep detonation down? Assuming a .0010 deck grind. Thicker gasket? Polish job to 80cc? Cut reliefs in the piston?

Please help if you can, I am trying to get the engine in the shop in the next few weeks and would like to bring in some options to discuss with them. I realize he is probably trying to keep it close to factory for warranty issues but I want to hop it up some.

Thanks!

 

Keep the compression down to 9:1 but you may be able to go higher with a big cam. A big cam will suck gas and you lose low end performance. The pistons may have to be machined to reach that figure depending on where and when you got them. Polishing the combustion chamber is "insurance" in my book and should not be counted on to prevent detonation. You can also raise compression a half point or so if you get proper quench which takes a lot of careful ma$hine work but the expense is not worth the gain.

-Just my 2¢

 

It's really the final static compression ratio you need to be most concerned with as Eric stated. I would stay under 9:1 for towing. match the cam to the ratio. Things like an Edlebrock Performer manifold and small 4V carb would help. Also headers but they can generate a lot of under hood temperature.

 

When I did my heads I relieved the area around the exhaust valves and then polished. I ended up with an 82cc chamber. I'm using the 941 crane, not what you would want to tow with. You didn't mention what you were planning on towing. My cr is 8.7 static and and 7.7 dynamic. I run about 12 degrees intitial timing and it will ping on 87 but not on 89 octane. If you were to go with the crane 901 or 921, both recommended for towing, and you had a deck clearance of .065 which is close to normal for a 400 and with Badgers you would probably be at about .075 where I am, you would be at about 8.5 static and 7.5 dynamic. That should run ok on 87 and certainly on 89. I am also at .030 over which changes it a little. you can play with this calculator if you want.
http://kb-silvolite.com/calc.php?act...8a4c4f13feafcd

 

Thanks for the help so far, such a wealth of knowledge that helps me feel informed when talking with the machine shop guys. It must drive them crazy these days though!

Anyway, I will be towing around 6-8000 lbs., mostly in Denver, over the mountains, and in the desert southwest, so the altitude effect should help. My cam choice so far is the Comp Cam 265DEH, with a Weiand dual plane and 600 cfm carb. It will have headers as well. One of his concerns was the quality of gas I might run into on a trip, which makes sense for a high comp. engine. Don't the Badgers mimick the 1971 compression ratio of 9 to 1 with no additional head work? The 265 cam is fairly aggressive for a tower, so from what you guys are saying that will help?

If I go in and say lets do the 265 cam, with its .510 intake and .526 exhaust, polish up the head to about 80-82cc's, and port match the headers do you think I should be ok? It has an NP435 so generating rpm's is not a problem in 1st gear, and w/o overdrive it will be humming in the 3k range on the highways, so a bigger cam should be ok for me.

I guess I could always keep a few cans of octane boost as well for insurance. It's not my daily driver, just the occasional tow and weekend show-off pleasure driving, so expensive high octane isn't as big an issue.

 

What gears and tires are you running? The 265eh may be alright if you have enough gear. Comp's web site does'nt give the intake valve closing and .050 so I can't tell you exactly what the dynamic cr would be with that cam. I would place a call to Comp and ask them what they think with your set up.

 

It has 4.10's, and 33" tires right now. The NP435 1st gear is around 6.69:1, so it revs quick when starting a heavy tow.

I found a spec sheet on the 265 saying this:


Camshaft Specification Table
Part Number 32-207-3
Engine 1970-1982 Ford
351ci-400ci
351C, 351M-400M,
8cyl.
Grind Number FC 265DEH-10
Description

Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.51 0.526
Duration At 0.006 Tappet Lift 265 275

Valve Timing At 0.006
Open Close
Intake 27 58
Exhaust 72 23

These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 211 223
Lobe Lift 0.295 0.304
Lobe Separation 110

Recommended Valve Springs 972-16

 

I saw that on their site but in order to get the dynamic cr you need to know the intake valve closing point at .050 tappet lift. It really won't make a huge difference anyway but you can plug that number into the calculator referenced above to get exact. The other numbers you need are your head chamber volume, stock is 78cc, piston head volume for Badgers is 5cc, headgasket thickness is .041, gasket bore is 4.08(I think), cylinder bore is 4.0 stock, deck clearance with Badgers and no block decking done will be about -.075, stroke is 4", rod length is 6.58,a nd then you need the above referenced cam figure.

 

I calculate a Dynamic CR of 7.62:1 with a 265DEH where the IVC angle is 58.5 degrees ABDC at 0.006". I used stock bore and 0.0565 deck clearance. A larger bore will increase the DCR slightly, more deck clearance will decrease the DCR. This should be OK on all but the lowest grade fuels.