Looking for advice, BB headers vs. HP manifolds

-
halfafish

halfafish

Damn those rabbits, and their holes!
FABO Gold Member
Joined
Aug 14, 2016
Messages
4,001
Reaction score
4,525
Location
SW Washington
I continue to pick the collective brain pool here, as I work on assembling a Big Block 69 Dart. No car yet, but I'm gathering parts.

The engine is a 383 intended to be nothing crazy. I want a fun street car with good manners and improved performance from stock, running on junk gas. It might hit the strip once in a while, but mostly it will be a street car with more emphasis on handling than straight line speed. Shaving weight up front is one of my goals. I plan on an aluminum intake, water pump housing and pump, and heads.

It will have manual brakes and steering and a 4-speed. Unless I am completely mistaken (always a possibility in my world :eek:), headers will offer the best performance. But in an A-body, there are issues getting them past the Z-bar. TTI appears to be the best fit option, and they do offer a modified Z-bar to help with fitment, but we're talking somewhere around $1000 or more for this setup.

A guy local to me has a set of B-body 383 HP manifolds for sale somewhat reasonably (asking $375). From reading on the Big Block Dart site, it appears I can fit these in an A-body by cutting back the steering shaft surround.

The question for the group has to do with performance and trade-offs. I think headers will give more performance but at higher cost and with fitment issues. Manifolds will likely fit easier, but probably weigh more. Would HP manifolds be a sufficient performance part for my build, or should I just wait and pony up the bucks for TTI's?
 
Headers for an all out race car.

In a street car, they are a pain from fitting, speed bumps & a lot of extra heat under the drivers feet.
 
For what you're describing, it sounds like a tossup between manifolds or a set of Schumacher tri-Y's... "Fun street" seems more manifold oriented. The old-school MP .528 solid cam is supposed to work well with manifolds, too.
 
Alaskan_TA said:
Headers for an all out race car.

In a street car, they are a pain from fitting, speed bumps & a lot of extra heat under the drivers feet.
Click to expand...
No. You are out of your area of expertise. For topics on documentation and stock type builds, I'd follow your advice.
 
Headers will always flow more than manifolds, but, as you say, you're build is mild and HP manifolds will fit the bill fine. I like manifolds for their permanence.
 
You could alway split the difference and go with something like TTI shorties.
 
I ran HP manifolds on my engines for years. Performance isn't really a problem with HP manifolds, you can make enough power with them to run a lot faster than most cars are legal for. But I eventually got tired of cooking valve covers and valve cover gaskets so I switched to headers. Fitting headers into a BB A body with a manual trans isn't going to be easy. I would not go with full length headers for your car. Some shorty headers or maybe a tri-y will work. The Schumacher headers won't fit out of the box with a Z bar but they can be modified. I'm not sure if Schumacher is still in business. Last time I checked he was out of stock of everything. I redid a set of Schumacher headers for my car so they would work with my Z bar but it took some hours at a street rod fab shop so it wasn't cheap.
DSC_3451 (Large).JPG
 
HP manifolds all the way. Get the biggest head pipes you can fit to muffs and then run 2" out the back. $375 sounds a little high from a friend but probably cant do better from a stranger.
magnums.jpg
 
AndyF said:
Fitting headers into a BB A body with a manual trans isn't going to be easy.
Click to expand...
Definitely not easy, if he wants to keep the mechanical linkage and z-bar... but the room is much improved with a hydraulic setup and a pull-type slave cylinder actuating the original fork. That's what I made and it allowed me to use cheap B-body headers :)
 
Thanks for the help guys, looks like I will go the HP manifold route. While I'm not a cheapskate, I do choose carefully where to spend my money. Manifolds are easier, cheaper, and let me keep the stock clutch (maybe with a TTI modified z-bar?).

pishta said:
HP manifolds all the way. Get the biggest head pipes you can fit to muffs and then run 2" out the back. $375 sounds a little high from a friend but probably cant do better from a stranger.
Click to expand...

The guy that has them is more of an acquaintance than a friend. He does have good stuff but his prices are generally in the upper range of things. I will snoop around but if I find a set here or on line, shipping would negate any price savings pretty quick.
 
halfafish said:
Thanks for the help guys, looks like I will go the HP manifold route. While I'm not a cheapskate, I do choose carefully where to spend my money. Manifolds are easier, cheaper, and let me keep the stock clutch (maybe with a TTI modified z-bar?).



The guy that has them is more of an acquaintance than a friend. He does have good stuff but his prices are generally in the upper range of things. I will snoop around but if I find a set here or on line, shipping would negate any price savings pretty quick.
Click to expand...
I wouldn't be surprised if you're talking about John (are local Mopar profiteer)..
I would inspect the living crap out of them..
Personally the only way I would put a big block in an a body is if I was trying to set the world on fire at the drag strip... All of that extra weight lack of room and inconvenience is not indicative of a "handling" car.. personally I would get the TTI's and tell John to eat those manifold for lunch... My-2...
 
I am looking for a good B or C body passenger's side HP exhaust manifold now, myself. I think they are priced way high. I will just hold out until I find one.
 
I had manifolds on a 451 in a 65 A and the thing was a beast, downright scary in turns. one little throttle blip and the *** was heading the wrong way. went to headers and it actually tamed the turns but I could not keep the smoke in the tires under anything but 2000 RPM and below. Went back to a warm small block. Much easier to manage and handle. Heck, I got a 6 in it now! 3 back is totally overkill. The exhaust has cooled and contracted enough within the mufflers that <2.5 is more than enough to get that out. 3 is a huge pipe and there aint alot of room for them back there over the rear and outboard of the tank.
 
pishta said:
I had manifolds on a 451 in a 65 A and the thing was a beast, downright scary in turns. one little throttle blip and the *** was heading the wrong way. went to headers and it actually tamed the turns but I could not keep the smoke in the tires under anything but 2000 RPM and below. Went back to a warm small block. Much easier to manage and handle. Heck, I got a 6 in it now! 3 back is totally overkill. The exhaust has cooled and contracted enough within the mufflers that <2.5 is more than enough to get that out. 3 is a huge pipe and there aint alot of room for them back there over the rear and outboard of the tank.
Click to expand...

I'm hopin mine will be a handful.
 
My 451 wasnt a stock 383 out of a station wagon: Max effort CNC ported iron heads, Crane .590 lift cam, 1.6 rockers, 9.8:1 compression, single plane Strip Dominator intake, 850 carb. 3.91 rear...hey those 205 tires didn't stand a chance! :p One of those mismatched combos that landed in my lap when a buddies storage unit had 6 hours left until they padlocked it and I had to grab what I could out of it. Couldnt get the Hemi 4sp out in time....
 
pishta said:
My 451 wasnt a stock 383 out of a station wagon: Max effort CNC ported iron heads, Crane .590 lift cam, 1.6 rockers, 9.8:1 compression, single plane Strip Dominator intake, 850 carb. 3.91 rear...hey those 205 tires didn't stand a chance! :p One of those mismatched combos that landed in my lap when a buddies storage unit had 6 hours left until they padlocked it and I had to grab what I could out of it. Couldnt get the Hemi 4sp out in time....
Click to expand...

Mine is going to be nothing like that. 9.5 compression. 240 @ .050 hydraulic cam. HP manifolds. "Some sort" of 750 carburetor. Mild as can be but somewhere it does "not belong".
 
When I ran HP manifolds in my car I had custom 3 inch head pipes built that cleared everything. They worked great for 20 years. Even had bungs for O2 sensors in each head pipe. These cost a lot of money since the flanges were 1/2 thick stainless steel and the piper were all hand cut mandrel bends, but that is what you have to do to have it last.
512a.jpg
512b.jpg
 
I saw a test where 3in. exhaust picked up a good amount on a stock 440 6 pack. Of course it was a flowmaster add. Take it at what its worth. I was thinking like 30+ hp over stock exhaust. HP Mopar did a drag test on tti 2.5 and 3in. ex. And the 3in. was worth almost a tenth over the 2.5 on a mild 360 but it did have headers.
 
IMO HP manifolds actually better than those "tri pipe headers".
Not worth the cost. For small diameter.
 
AndyF said:
When I ran HP manifolds in my car I had custom 3 inch head pipes built that cleared everything. They worked great for 20 years. Even had bungs for O2 sensors in each head pipe. These cost a lot of money since the flanges were 1/2 thick stainless steel and the piper were all hand cut mandrel bends, but that is what you have to do to have it last.
View attachment 1715464019 View attachment 1715464020
Click to expand...
^Darn nice , but u know for sure it would have probly made 40 more h.p. with 2" headers !-----------Just for those advocating the high performance cast iron manifolds , which I think suck >---jmo
 
aaronk785 said:
I would do at least 2.5 pipe all the way out the back. 3in. would be better yet.
Click to expand...

IT's only as good as the collector size. No point in my opinion in running bigger than collector diameter. On the flip size of that I do not agree with the concept of chocking a 3.5 collector down to a 2 1/4 or 2.5" either.
 
Good points from all of you, and again thanks for the help and insight. I will take these tips as I move forward.
 
AndyF said:
I ran HP manifolds on my engines for years. Performance isn't really a problem with HP manifolds, you can make enough power with them to run a lot faster than most cars are legal for. But I eventually got tired of cooking valve covers and valve cover gaskets so I switched to headers. Fitting headers into a BB A body with a manual trans isn't going to be easy. I would not go with full length headers for your car. Some shorty headers or maybe a tri-y will work. The Schumacher headers won't fit out of the box with a Z bar but they can be modified. I'm not sure if Schumacher is still in business. Last time I checked he was out of stock of everything. I redid a set of Schumacher headers for my car so they would work with my Z bar but it took some hours at a street rod fab shop so it wasn't cheap.View attachment 1715463675
Click to expand...


Andy,
What do you think are the power level limits in each setup?
manifolds vs 1-5/8' step ?
 
You must log in or register to reply here.
-

Back
Top