How much extra horse with headers??

[Supercharged]

I have built a 340 that has been machined .030 with KB pistons, 10:1 comp, mp 284/484 cam, x heads that have been ported massively, 2.02/1.60 valves, I'm running msd 6al and blaster 2 coil, 650 dp holley, factory port matched intake, and exhaust manifolds, and a holley electric fuel pump. My question is with this setup how much would I gain with headers, and what type would fit without any modification. The motor is in a 70 Dart swinger. Also my power estimations are 375 is this high? Thanx for the info

Mike

[kingjr]

I don't think those #'s look high. Add a set of headers and I'd guess you'd top 400hp, gotta let that thing breath! Looks like a solid setup. Had the same cam/combo 20 years ago, loved it!

[Supercharged]

Thanx alot Kingjr. Anyone else have any opinions, and also what type of headers. It is a driver but is also a show car so, I cannot be denting my headers with a hammer, they MUST look good! :-)

Mike

[rumblefish360]

I've heard said through the years to add 15% to the power figures with headers. As a ruff guess I'd say you'll make about 430+ HP.
A set of headers from tti should do the trick. The headers are built right as where the old ones were a dent and fit. Nothing more than that!
TTI has a great rep. The cost a bit more than the adv. dent & fit units. But its worth it. They also have exhuast pipes that run end to end including tips. Pipe sizes vary from2 1/2 -3 inchs with or without mufflers.
ttiexhaust.com

[Supercharged]

Great, I'll check out the link. Thanx alot Rumblefish.

Mike

[Plum Crazy Chris]

Sounds like a nice package!

A 650 carb seems a little small for your application. I would think with headers on it that a 650 is really going to limit you. I would step up to at least a 750 and maybe a 800 cfm carb. Mopar Performance went from 750 TQ to a 800 Edelbrock and picked up 25 hp with a setup very similar to yours. It would be a quick test swap after the headers are on to find out. I think you would notice 25 horses in the seat of your pants without going to a dyno, or the track.

From what I hear the TTI headers are the way to go, especially with an A-body.

[Supercharged]

Thanx for the replies guys, I was hoping to get a 13.9 on street tires at the track with the stock exhaust manifolds. and hope to get 13.5 with headers.

I checked out numerous carb sizes and everytime it checked out to be 650 dp. I guess trial and error is the only way.

I could dyno it I guess, a local speed shop has a dyno, they charge $350 for 4.5 hours with 1.5 hours set-up time, then you get about 3 hours of tuning time. But I'd rather put that money towards the headers.

Mike

[Duster_340]

Hey Mike,
What part of the city are ya from. I live in Fort Richmond. have a Duster 340. I am running the manifolds. tired of header hassles, although the tti are good if you can afford them.

[Supercharged]

Hey Duster_340 I actually live a few mins out of the city on the east side of Deacons corner! Are you going to test and tune in Gimli on Saturday? I'll be there!

Take it easy

Mike

[PRO]

SC,lets say your car weighs 3100 lbs,itll take 225 rwhp in ideal conditions(traction,gearing) to go 13.95 et,you usually give up about 75hp thru the drivetrain,if you made 375 at the crank that would be about 300 at the wheels which would give you a 12.68 et.Youe combo is screaming for headers,remember if a stock 340 went faster with headers it tells you the manifolds are restrictive,if you port heads(massively)and add comp and cam the manifolds become even more restrictive,adding headers will probably net you almost 40hp,of course then youll need a bigger carb,something around 750cfm which will add another 10 hp or so.Right now Id estimate your combo at 325hp at the crank,add headers and carb and youll be 375 at the crank,300 at the wheels which should easily put you into the 12s.........PRO.....ps,for car math calculators go to www.Prestage.com

[Supercharged]

Hey Pro thanx for the reply. Are you talkin on street tires or on slicks. With the same set-up but in a 72 Duster 340 we run street tires uncapped at the track, with the snubber an inch away from the top plate, and the rear clamps off the springs, and the tires aired down to 12 ibs. Our best time is a 13.5. Thats with a 60 ft time of 1.95. Our problem right now is spinning out of the hole.

I'm going to have to get the tti headers, I guess. They will cost me close to a $1000 Canadian by the time they get here. But I have to be sure they will fit without modification. If there is anyone out there that uses the tti headers on 340 in a 70 Dart please post and let me know how the installation went.

Also the manifolds have been port matched to the heads, and the intake also, this should help it breath better than stock right. Any opinions?

Mike

[PRO]

Hey Mike I was talking ideal conditions,slicks perfect gearing and no wheel spin,1.95 for street tires isnt anything to be ashamed of.The fit of TTi is superb!!! Port matching the intake will give some real world increases but port matching the intake is somewhat useless because the restriction is in the final outlet diameter............PRO.....

[Supercharged]

Hey Pro, you've been a great help thanx alot.

Were taking the Duster to the track on Saturday, The current set-up. No back seat, front valance taken off, sway bar taken off, rear clamps taken off the springs, little race cell battery only weighs 10 ibs! and running the tire pressures at 14, 12, and 10 pounds to see which will hook best, and set the pinnion snubber up so it will be about half an inch from the plate. Also we are running open headers at the track. The car will be driven to and from the track, hour drive each way.

Also went and weighed the car after all that, and to my surprise it still weighed in at a hefty 1475 kilograms which translates into 3251.785 ibs thats without a driver and about 1/8th tank of gas. Pretty heavy!!

I'll take some pics and post them here when I get them back from the Developers.

Mike