Torque Monster 390

[fomocoguy]

Well, after my recent score of engine parts I am seriously close to beginning the assembly of my 390 for my crew. I've got a good idea of where I'm going with it, but I thought I'd get some input from you guys on induction and exhaust options. Here's the rundown:

1965 352 block bored to 4.05 (390 std bore)
390 4v pistons to achieve ~9.4:1 compression ratio
torque RV type cam
basic valve job on heads

Now, the idea is to build a motor for serious torque. I don't plan to win any races; I just want to pull 5000 pounds up a grade and not have traffic backed up behind me. So, that being said I have a few options for the intake side. According to summit's carb calculator, my 390 with a max rpm of 4500 only needs about 406 cfm (at 80% volumetric efficiency). I already own a Performer intake and a 600 Holley and Edelbrock. My options (as I see them) are as follows:

Stock two barrel intake with a 424 cfm autolite 2100 (or possibly a 500 Holley two barrel)
Stock four barrel intake with adapter and the same
Performer intake with adapter and the same
Stock four barrel intake with 600 carb
Performer intake with 600 carb

Any other ideas?

Now, on the exhaust side I really don't like how crowded the starter is with my long tube headers, so I'm gonna change it out. I'm thinking either to splurge on some sanderson shorties or use the stock manifolds. My only thing is I really hate the passenger side log design. Have any of you ever heard of flipping one of the drivers side ram horn manifolds for the passenger side? Any other Ideas that are cost effective?


Thanks for any input!

[1971ford]

Sounds like you are doing a very similiar build to me.
Just curious, I thought that using 360 pistons in a 390 was a good idea for getting torque, but i see you have 390 pistons on the plan.

[fomocoguy]

Sounds like you are doing a very similiar build to me.
Just curious, I thought that using 360 pistons in a 390 was a good idea for getting torque, but i see you have 390 pistons on the plan.

That's because partial skirt 360 pistons ARE 390 4v pistons. I just didn't want to confuse anybody and get into something that wasn't part of my questions.

BTW, I posted this with you in mind also since we're doing the same build. I know any of these intake setups will work well, but I just want to know which one is the absolute best for torque!

Oh yeah, does anybody know the cfm capabilities of the stock two barrel intake?

[Fordtastic]

Your post urged me to google and find a carb calculator.
how did you figure out your VE %? im sorry this is off your topic but I was curious how it all worked.... you have your max rpm as 4500? doesnt it red line at 5500? If my questions are a bother please ignore

(looks like my carb is huge for my lil 302..... 600cfm holley 4bbl..... )

[Ks Highboy]

Could you go with a mini starter from Summit to get you some extra room with the headers. I really hate to see you put manifolds back on a 390 as these are killers of hp and tq. Also, I would opt for the performer/Holley combo.

[fomocoguy]

Your post urged me to google and find a carb calculator.
how did you figure out your VE %? im sorry this is off your topic but I was curious how it all worked.... you have your max rpm as 4500? doesnt it red line at 5500? If my questions are a bother please ignore

(looks like my carb is huge for my lil 302..... 600cfm holley 4bbl..... )

Well, the calculator I used is this: (engine displacement x Max RPM) / 3,456= ideal cfm. Street engines run at about 80% VE.

I chose 4500 rpm because I'll probably never run it past that. It's probably not going to make any more power past 4000 the way I'm building it, so there is no need to.

If your carb is vacuum secondary it is fine, only because vacuum secondary carbs only give the engine what it's asking for (in basic terms) according to the manifold vacuum.

[Doug F]

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

[fomocoguy]

Could you go with a mini starter from Summit to get you some extra room with the headers. I really hate to see you put manifolds back on a 390 as these are killers of hp and tq. Also, I would opt for the performer/Holley combo.

Well, I thought of that too. It would save me the $$ for the sandersons, that's for sure. Today I did a little research on some manifolds I have and realized there is quite a differance between the car and truck manifold. I know it's not as good as a header, but check it out:

The top is a truck manifold and the bottom is a car. In the truck manifold the last cylinder actually has to fight the other three to get it's exhaust out, moving foward first then out. On the car manifold it only has to turn. Not great, but much better than the truck. See:

In the bottom manifold you can actually see out, where on the top one you just see metal blocking the path.

If I do go back to manifolds, I think I will use this car one on the passenger side.

All I know is that on my 360 I actually lost a bit of low end with these headers and 2.25 duals with a crossover. I was very dissapointed. I know this 390 will be a different animal, but it still erks me....

[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

COOL! Do you know a price? It's already got spintechs on it.

[Doug F]

No price unfortunately... Haven't gotten to that point yet. Give them a call! Tri-Ys are the **** for torque building!

[sideoilerfe]

The manifolds will work fine for low rpm torque under 4500 RPMs. You can spend the money on headers if you want but I did that before and noticed NO performance/ mileage gains whatsoever. To each his own.

[fomocoguy]

The manifolds will work fine for low rpm torque under 4500 RPMs. You can spend the money on headers if you want but I did that before and noticed NO performance/ mileage gains whatsoever. To each his own.

That's the exact thing that happened when I put the headers on my 360. Basically 8 hours of work for nothing.

[dustman_stx]

The manifolds will work fine for low rpm torque under 4500 RPMs. You can spend the money on headers if you want but I did that before and noticed NO performance/ mileage gains whatsoever. To each his own.

That's the exact thing that happened when I put the headers on my 360. Basically 8 hours of work for nothing.

I did the opposite. Pulled a 360 from one truck, left it exactly the same except for the exhaust. Went from headers to manifolds. Noticed a HUGE loss. Feels like 50 horse or better. Engine used to pull hard to 5400, now it's dead by 4000.

It's stock compression, stock heads with hardened exhaust seats, Performer RPM, Holley 600cfm, Pertronix Ignitor 2 ignition slightly larger cam than stock.

Edit:
Just noticed your 4500 RPM statement. I'd say with my experience I get similar power to 2500. I would venture to say that, at least in my case, if you'd dyno'ed the two, you'd see the headers and exhuast start pulling away from the stock exhaust hard at 2500 for the rest of the power band.

[fomocoguy]

The manifolds will work fine for low rpm torque under 4500 RPMs. You can spend the money on headers if you want but I did that before and noticed NO performance/ mileage gains whatsoever. To each his own.

That's the exact thing that happened when I put the headers on my 360. Basically 8 hours of work for nothing.

I did the opposite. Pulled a 360 from one truck, left it exactly the same except for the exhaust. Went from headers to manifolds. Noticed a HUGE loss. Feels like 50 horse or better. Engine used to pull hard to 5400, now it's dead by 4000.

It's stock compression, stock heads with hardened exhaust seats, Performer RPM, Holley 600cfm, Pertronix Ignitor 2 ignition slightly larger cam than stock.

Edit:
Just noticed your 4500 RPM statement. I'd say with my experience I get similar power to 2500. I would venture to say that, at least in my case, if you'd dyno'ed the two, you'd see the headers and exhuast start pulling away from the stock exhaust hard at 2500 for the rest of the power band.

Well, that helps because the one big differance is my 360 still has the two barrel on it, so I'm sure that is my restriction point. That's probably why it's dead at 4000rpm as it sits. Since the headers are already installed on my truck I may just get a mini starter for it. The only thing I don't like about that is I like the idea of walking into any parts store from here to california and picking up a replacement starter for it and being able to install it easily without having to unbolt a header completely, and I can't really afford two mini starters just to have a backup.

Thanks for the info! You can't beat first hand experiance.

[fomocoguy]

The manifolds will work fine for low rpm torque under 4500 RPMs. You can spend the money on headers if you want but I did that before and noticed NO performance/ mileage gains whatsoever. To each his own.

Ok, so now I have to ask: was this a stock 2 barrel or did it have a 4 barrel on it?