Torque Monster 390

[sideoilerfe]

That one was a 2V. My current 390 has a 4V and has no problems getting to 5800 rpms with manifolds. The difference with headers was at high rpms like 4500 or so but it wasn't that much. And with headers you loose the bottom end. IMO, the slight gain in HP in the top is not worth all the torque loss at lower rpms or all of the trouble you get with headers.

[fomocoguy]

Well, my real dilemma is that I don't like my currant headers and I'm trying to use as many parts as I can that I've already got on my shelf. Just out of curiousity what intake are you running and what size/brand of carb? How happy are you with their performance?

[sideoilerfe]

Stock cast iron 4V intake with a Holley 600 cfm vacuum secondary. Works fine.

[hazelnut]

Have you thought about old factory cast iron shorty headers,i dont know how much they cost today? Seems like it would be a good choice for you if there not to high priced now. My truck is like yours but not a crew and was thinking when i put mine back together of useing factory shortys if they would fit inside the frame and clear the clutch.

[Doug F]

Long tube headers are for higher RPM ranges such as in cars... Tri-Ys are like enhanced manifolds, small short tubes going into longer tubes and then into a long collector tube that enhances scavenging. Long tubes usually also have 3+" collectors which are free flowing, but not efficient on the bottom end. The Tri-Ys have (on average) 2 1/2" collectors, not requiring high RPMs to keep the flow up.
I live at altitude, so I have to make sure everything is working in unison or I will have a poor performing truck. I had built engines for years, at sea-level and was running a 750 cfm on my 289 with 351 heads and roller cam with a C-4 in my 67 Mustang. It only weighed 2200lbs, even with 2.80 gears, it didn't bog and ran up to 6000 rpms all day long.

I am currently designing my 352 to run up here, which will include a Comp Cams XE 262H cam, 570 CFM Holley or 500 CFM Edelbrock 1404, Holman Moody MR 427 single 4v manifold, gasket matched heads, FlowKooler water pump, windage tray, Underdrive pulleys, FPA Tri-Y headers.

[fomocoguy]

The tri-y's are really cool; I just doubt they are in my budget. I'll have to find out...

[fomocoguy]

Have you thought about old factory cast iron shorty headers,i dont know how much they cost today? Seems like it would be a good choice for you if there not to high priced now. My truck is like yours but not a crew and was thinking when i put mine back together of useing factory shortys if they would fit inside the frame and clear the clutch.

I have seen them all over ebay and they are PRICEY. We're talkin 500-700 bucks for a set of factory cast iron shortys, about 1/3 of that for 390 GT manifolds. The real problem though isn't the price; the bolt patterns are completely different, so if you were going to use them you would need the matching type of heads (like from a 390 GT or 427 car).


EDIT: Sorry, the 427 style cast headers do have the correct bolt pattern; it's only the 390 GT manifolds that do not.

[fomocoguy]

If God was building his F-100 Bump up, he'd use these Tri-Ys. Second from the bottom.

http://www.fordpowertrain.com/FPAindex/headers1.htm

I am putting these on my truck (when I get to the exhaust) then, since it is a 4x4, 2 1/2" mandrel bent tubes under the bellhousing, into a Dr. Gas X-Tube (he invented it), SpinTrap mufflers and oval the pipe and run it out at a 45 to just in front of the rear pass tire.

http://www.spintechmufflers.com

FYI, the bare tri-y's are $495, coated are $695 plus $55 shipping. That's about what I'll have invested in my total build....

[Doug F]

That's about right for custom headers... Is yours a 2wd?

[1971ford]

his is a 4x4. It's his 4x4 f250 crew.

I'd sure like to have those headers under the christmas tree

[fomocoguy]

I also asked if you still have to unbolt the header to remove the starter and he said yes and that a mini starter is the way to go.

I've pretty much decided to go back to manifolds; I just haven't decided which ones yet...