Header Size?

[streak]

Hi guys need to know your opion on tube sizes on headers. I'll be installing a 427sbc in a chevy Luv and will probably have to build custom headers for over the frame, The heads are Brodix Track 1 M2 227cc and was thinking 1.875 dia. tubes what do you guys think.

[18436572]

Sounds right. A rule of thumb I have always heard was to keep the header tube diameter near the same as the exhaust valve diameter. With 1.88" ev, the 1 7/8" tubes should be perfect. What size collectors and primary exhaust pipes to the mufflers? I would run 3" collectors to 3" primary exhasut pipes. No more than 18" from collector to muffler. 2 1/2" exhaust pipe after the muffler. Use a crossover pipe before the mufflers of 3" diameter in the 'H' configuration. Flowmaster mufflers unless you are making over 550-600 hp then I would use Magnaflow mufflers (straight thru design). These are my opinions. Hope it helps.

[streak]

10-4 that does help. I won't be needing mufflers this will be stricky open header and as high as my front end will be I should have enough room too bring a set of over the frame headers down and kept them tuck in tight.

[pat mccarthy]

well the EX valve size s for you SBC would be 1.600 or 1.625 so if you add .100 to that that will get you a 1.725 or 1.750 that would be 1.3/4 so less you have the room you could go to the 1.7/8 tube that starts getting tough on some heads but i think your heads are spread ports and drilled for the stall header plate so getting that size+ would not be hard . i would build them as a step header s and run a 3 1/2 collectors rpm would help on the building of the headers so 1 7/8 to 2.00 or 1 3/4 to 1 7/8 or say to hell with it and run 2.000 if it is a hi rpm with a trans brake + 5000 stall lite truck? first thing i do is look in to the build and see what others have used and HP numbers they have nailed down less you want to build two sets and buy dyno time .i built headers and that how i went at it less the customer had numbers and i built them there way for tube size primary length some guys just wanted headers to fit the engine they had

[streak]

Thank's guys for the info, Trying to think everything out and plan ahead for all the work that's going into this build. I can fab up and weld anything that needs to be done and I want this little truck look as good as it's going to perform.

[streak]

Up date, A frend of mine just gave(free)me a set of Stahl 17/8 dragster upswept headers with adapter plates he said they have been in his shop for years and was tired of looking at them. I went home and kinda placed them in the fender well upside down over the frame where the sbc should fit and maybe just maybe they'll work with a few soft words and alot of HOPE.

[streak]

OK guy's need your advice again, I found out I can order a set of over the frame fenderwell headers made for the truck but they are only 15/8 dia tubes and I don't know if thats going to be big enough too get the air out fast enough.

[pat mccarthy]

well if you want to play the ex valve size game by header tube size you EX valve could be 1.600 or smaller so 1 5/8 is 1.625 there ok for street use or mild build but are to small for a big CID smalll block

[camaro_fever68]

If you don't have spread port exhaust, you can get 1-3/4 Hooker SuperComp's for your Luv but they are not fenderwell exit. I run them on mine with exhaust. http://www.jegs.com/i/Hooker-Headers...oductId=744807

[streak]

Well I pretty much knew the answer just getting alittle lazy in my old age, When I get the engine in I'll try the Stahl headers and if that don't work I'll just have to build a set.

[streak]

Thank's for the info on the headers from Jegs(2140) they won't fit I got angle plug heads, some guy's say they use some for camaro's but don't know what #