what size header to run

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daves 72 dart

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what size header should i run on my 340? block
Work done: O-ringed, tubed for roller cam, oil gallies enlarged, bored to 4.07(.030 over) and honed with deck plates by Herb McCandless.

340 steel crank
Prepared by Lunati, stroked .110 to 3.42 stroke and balanced to 8000 rpms

340 steel rods
Prepped by Lunati. Hand picked set. All are within .001 of each other in length. Bronze bushed, balanced and lightened.and shot peened.

Heads
340 X heads with 2.02 intake valves and 1.60 exhausts. Double springs for .700 lift cam, Maximum porting on intake and exhaust ports.Ports are 63cc combustion chambers. they flow 260 cfm

Pistons
Venolia lightweight forged pistons. Uses dykes top ring, 1/16 2nd ring and standard tension oil rings. Weight is 510 grams.11.3 comp

Intake
Holley Strip Dominator ported to match heads.the carb is a bigs 950 stage 5

Camshaft
Cam Motion roller 269 275 @ .050 and .631 lift with 1.5 rocker Valves set on .024 .028
RPM range 4500-7500. Cam is degreed in at 104 deg centerline.

Other Parts
High volume Melling oil pump, Comp Cams roller lifters, Crane 1.5 roller rockers(gold), Fluid Balancer, windage tray, Cloyes double roller timing set. SCE copper head gaskets(.060). Tall valve covers for use with roller rockers. Moroso 8 qt deep sump oil pan. Bronze cam gear for use with roller cams.i plan on shifting at 7200.im hoping for low 11s.this is going in a 72 dart with a 727 trans, 4900 stal,8.75 rear with 4.88 gears
 
Low 11's....i wouldn't count out mid 10's if tuned properly,as for headers tti makes 1 7/8 tube headers now...
 
With so much passion and $$$$ put into that combo, YOU would be foolish to install a prefabbed header.

Get a "custom length header/collector" made, that matches the rest of the combo.

There is a program out there By Larry Mueax called PipeMax that will predict the exact length of primary tube as well as collector.

I thing its around $40, Larry is planning on releasing newer version this year.

The $40 one, has vary good information and will help predict induction lengths as well!
 
I was going to say, if you can provide teh details on the heads and cam timing events i'll run it through pipemax...lol
 
moper said:
i was going to say, if you can provide teh details on the heads and cam timing events i'll run it through pipemax...lol
Click to expand...

lol 8)

I'm looking forward to the new one with 1/8 miles spec!!!!
 
combo looks good but what kinda open spring pressure are you running cause I wouldn't run those Crane rockers they will egg shape on you and break and you will have more problems.
 
you will also have to shift it higher than 7200rpm.I would run a 1 7/8 header about 29-31 inches long and 3in collector about 15-17 inches long.

DSC_3565wtmk[1].jpg
 
I'm gonna guess a 1 3/4" tube, 32" long and a 3.5" collector

Auto car might like a little longer tube
 
what kind of details on the heads and cam timing events do you need/mean?
Click to expand...

I'm going to speak out of turn and say moper will need cam center line (lobe center angle), as well as what you degreed the center line too.

What compression ratio (SCR)

Ammm...............and Valve Stem Diameter.

I thing all the rest is in the OP.
 
crackedback said:
I'm gonna guess a 1 3/4" tube, 32" long and a 3.5" collector

Auto car might like a little longer tube
Click to expand...

crackedback, i wanted to load "dave's 72 dart" spec's in to PipeMax, and see how close your guess was..........and it's still a guess as i had to GUESS on some of the spec's in PipeMax.

1.764-1.889(1 3/4-1 7/8 ) Tube Diameter, 29.9"-31.8" long, 3.236"-3.486" collector diameter.

considering accuracy, being slight off in Pipe max due to guesses, Your guess was right there!!!!!!:cheers:
 
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