[NYGTO]

The headpipes on my car are nearly finished with there service life. I'd like to replace them with the 2.5 inch headpype from Pypes and then add the Dump Legs.

The caps then could be opened off the end of the headpipes enabling the exhaust to exit completely straight .

This seems like a good approach and I would use the caps without the electric kit.

I'm trying to coax my stocker towards 13.50.


Am I on the right track here with this set-up?

. See illustration., thanks

[punkin]

Maybe this will help

https://youtu.be/t8J17lCerH8

[NYGTO]

That's a good video and with quite surprising dyno results. I'm comfortable with how to move forward. Thanks

[straycat]

NYGTO You got me thinking.

[TheSilverBuick]

I put those on my Buick 455 over ten years ago. I have electric cut outs and would do it again. Its 3" through the cutouts and 2.5" x-pipe and muffler.





https://youtu.be/5lQ2fpHvCSE?si=n6fZCKgFVqN4gFzV

[Formulajones]

I have electric cutouts on 5 cars and cutouts ready to accept more electric doors on 3 more.

One of the best bolt ons I've put on a car.

[Jim Moshier]

what cutouts are you using? where from?

[indymanjoe]

these are going on my car in the next week or so.

https://dmhperformance.com/ecutout.htm

[Formulajones]

I've had DMH's on my Chevelle for about 25 years now and they've been flawless.

I used to live up the street from Dave. Back then he ran his shop on his property and I'd just drive over and pick them up. Super nice guy.

[Formulajones]

Oops sorry didn't see your other question.

I have DMH on the Chevelle, Quick time on all the other cars except one, that one has a set that Jegs sells under their name. Those kind of slightly leaked a little when first put on but carbon buildup seems to have sealed them up now LOL.

They all work great though. Quick Time seems to be easier to get as most places sell them. I don't think Dave sells his brand at any of the vendors, it's only straight from him if I remember correctly. But they are nice pieces. Only thing that turns me off from DMH now that I don't live close to him, as I need another set for another car I'm working on, is that he doesn't take credit card. Only paypal or something like that, and I don't do paypal anymore.

[straycat]

Just to follow up on NYGTO post saw him at Island Dragway several weeks ago. Believe he picked up 2 tenths. Mine going on 65 Tempest in time for testing at Norwalk.

[NYGTO]

Yes Staycat I picked up 2 tenths and 1.5 mph. I'm trying to see how fast I can go under 1965 NHRA C/S rules. It's pretty narrow

Don't go to fast I'm trying to catch you! :--)

[indymanjoe]

I.ve had the ones i posted on for about 9months now. Absolutely love them. I put the switch in the console but i think i may wear the switch out as i use it All the time lol

[Formulajones]

Okay long post but, As far as power differences go, it's seems to be reliant on how efficient the rest of the system is and whether it's sufficient for the engine. I have several examples, I'll just list a few.

My sons Vega with a nice little 500hp 327, has long tube headers and the exhaust is a 2 1/2" transverse kit for an F-body that I shrunk down to fit the Vega. I ran this same system on my Firebird decades ago and kept it knowing it would go on another project one day. It went on his vega. I installed a pair of Quick Time cutouts about 20" behind the header collectors. Through the exhaust it ran a best 12.77 at 107 mph. The very next pass without a cool down he opened the cutouts and it went 12.40 at 112 mph. The MPH is the telling part. https://youtu.be/M-5PPMnodzQ

My sons mustang has a full 2 1/2" Dynomax kit on it with a BBK "X" Dynomax mufflers and factory looking 2 1/2" tails. On the chassis dyno the stock 302 made 230 HP to the tires, with the cutouts open it made 232 HP to the tires. Not a huge difference so the exhaust is doing a pretty good job on a stock 302.

My 69 Z/28 with it's stock 302 is running Pypes transverse system with an "X" and I installed cutouts on this one. On the chassis dyno it made 277 hp and with the cutouts open it made 284. Not a huge difference.

My Chevelle with a 598, a 3 1/2" exhaust into and out of the X, into a pair of 3" dynomax ultraflow mufflers and 3" torque tech tailpipes. I positioned the cutouts straight back from the header collectors before the bend into the "X" and are about 20 inches from the header collectors, It ran a 10.90 at 123 through the exhaust, I opened the cutouts and it ran a 10.90 at 123 LOL
So that exhaust system is working excellent for that engine.

That's not to say I wouldn't put cutouts on a car even if the performance is marginally the same. They are a hell of a lot of fun on the street, I use them all the time. They are great when a loud mustang or hemi comes up with that awful cackle obnoxious exhaust and I hit the switch and can't hear them anymore