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https://slantsix.org/forum/viewtopic.php?t=60272		 Page 1 of 1
Author:  bigcasey123 [ Wed Oct 05, 2016 6:37 pm ]
Post subject:  header options
okay so i have a 69 dart super 6 225. i am planning on buying a pretty bad motor from a guy that makes around 300 hp. now it is naturally aspirated and definitely needs split exhaust. the problem is i have power steering so headers are gonna be tricky and i dont know if dutra duals would be too restrictive for me considering i would like to try to get this car near the 13s. but that motor wont be going in for a while s my super 6 will be running on this setup for a while... i dont think that will change my decision too much. what are the best options? and do i go 2in duals or 2 1/4?
Author:  DusterIdiot [ Wed Oct 05, 2016 8:40 pm ]
Post subject:  Well...
Overall, headers will be required to get the most out of that level of motor... but you will lose your manifold heat and make fall and winter driving (and starting) a bit of a challenge...

Dual Duals will work, but the challenge is getting the rear pipe to clear over the top of the high mount starter.... you also lose your manifold heat here too...


The headers if typical late A-body will have 2 1/4" collector outlets...

Dual duals will get tight on 2 1/4" pipe...most people will do 2" pipes here...

Also you will have to make a decision on the mufflers if trying to street drive this... you may need a set of cutouts ahead of the mufflers when racing...

Given it's a light 67-72... you might think about pulling the power steering and installing a firm feel manual box with the column shaft adaptor ....
Author:  coconuteater64 [ Thu Oct 06, 2016 7:09 am ]
Post subject:  Re: Well...
Quote:
Dual duals will get tight on 2 1/4" pipe...most people will do 2" pipes here...
Yes! I did 2 1/4" and it's tight even on a truck. It's a really tough bend to make even with professional equipment. IMHO, for that type of engine headers are the way to go.
Author:  slantzilla [ Thu Oct 06, 2016 9:18 am ]
Post subject: 
What header was he using to get 300 horse? That would be my first choice. With a '69 Dart most any available header will fit. Hookers with a 2-1/4" exhaust would be my choice.

The very first thing to do if you want to run 13's N/A with a streetable car is start cutting out weight.

Is the car a stick or auto? Stick will need a good clutch and flywheel, auto a really good converter. Both will need at least a 3.91 gear in the rear.
Author:  Badvert65 [ Thu Oct 06, 2016 10:06 am ]
Post subject: 
What was done to get 300 horses? This might dictate trans, gearing, and exhaust requirements.
Author:  bigcasey123 [ Thu Oct 06, 2016 11:00 am ]
Post subject: 
i think now im just gonna buy the race head from him. otherwise it might not be very streetable. big valves ported and .100 shaved off. then ill get something like an ocg 819. plus my 2bbl but maybe upgrade to a 500cfm. then i think 2 in dutra duals would work right??
Author:  my5thmopar [ Thu Oct 06, 2016 11:18 am ]
Post subject: 
Quote:
What was done to get 300 horses? This might dictate trans, gearing, and exhaust requirements.
I'm wondering that too. That has to be some serious modification.
Author:  Rick Covalt [ Thu Oct 06, 2016 12:50 pm ]
Post subject: 
turbo motor I think
Author:  DusterIdiot [ Thu Oct 06, 2016 5:00 pm ]
Post subject:  Yes, but...
Quote:
big valves ported and .100 shaved off. then ill get something like an ocg 819. plus my 2bbl but maybe upgrade to a 500cfm. then i think 2 in dutra duals would work right??
Here you have to watch out, because the intake's runners aren't that big... I ran into that problem after having the head's bowls waddled out and doing some major port work on a lower compression motor with milder cam... it was doggy at the low rpms, but worked great after 2000 rpm...(lower runner velocity was not supportive of daily driving...), later I swapped that head onto my 11:1 fat pak motor and boy that did the trick...(but I wouldn't drive that on the street...)
Author:  bigcasey123 [ Thu Oct 06, 2016 7:04 pm ]
Post subject: 
It was not a turbo motor. But I decided probably not streetable. Huge cam like .510 lift and high duration. Plus it was bored and a lot of head work. That's what the PO said.
Author:  slantzilla [ Fri Oct 07, 2016 12:51 am ]
Post subject: 
Not to pee on your parade, but a .510 lift cam is not huge. It is also not anywhere near enough camshaft to support "near" 300 horse. It will support 200-225 very nicely and have decent street manners.

Most any Slant block can be safely bored +.100". Boring in itself does not increase performance a whole lot. It is mainly to give nice straight cylinders that will seal up well.

"A lot of headwork" may or may not be a good thing. Too much grinding in the ports can really kill flow. IF the head was not put on a bench and flowed, it is a crapshoot.

Did the guy offer any documentation on this motor or is it just his word?

Just curious. :D
Author:  Killer6 [ Sat Nov 26, 2016 12:42 pm ]
Post subject: 
Agreed. Does this person have anything to back that up at all, like timeslips,
dynosheets, etc.? Have you even heard it run? Was this on pump premium?
He didn't/couldn't tell you the squeeze? 12.5:1 would not be streetable, no
matter what headers, unless you plan on race fuel. And you can't just plop
that head on your engine w/o knowing a lot of details, you mite need shorter
pushrods etc. You've got a lot of homework to do before worrying about
pipes........
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