Thread: Engine setback

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Originally Posted by pat mccarthy

oval tubing. but still would be a pain and the you still have to run some type of muffers. you would have to run a y pipe off the headers .run it down the pass side and still get it out side of the car .if you want it low to the ground . or cut the floor build the ex. then build floor back over it

Yeah, thought of that, too. Think the outsiders will end up being easier to build and should certainly be more efficient for the engine.... I did what you suggest on Joe's Camaro with the LS engine....2 1/2" from the headers to a Y pipe, then 3" to the rear axle, another y pipe, and dual 2 1/2" pipes out the back. Worked out good, sounds great, but just seems like to much restriction.... With the outsiders, would be simple to run step headers and/or 4 into 2 into 1 Tri-y's or 4 into 2 into 1 merge collectors..... Think I'll do the outsiders, maybe even send them off and have them coated?????

out side will work the best .i think if you did aY to oval 4 1/2 inch then back to a y mufflers out. it would work good i wanted to do a big oval ex for the gto but the car just is not that low. it sure would be cool . but it is $$ there is somethings i will spend money on if i can see it .i tell you on the chevy the car sit low in the front .i never cut the k trans crossover out was to strong to take out .so the ex kick down to the headers and kick back up over the cross member was not a big deal with small ex like 2 1/2 but with the 4 it down. it just cheap steel tubing. the roads are so bad that i use it as a skid plate ever now and then better then my oil pan

My "Z" is 47" tall. I can just slide my fist under the 4" collectors. Step headers pretty much fills all the available space inside the front tires to frame, but they still clear turning the wheel lock to lock. . Crank centerline is 11'' to the floor. The headers dump outside the 2''x3'' frame rails so I plan to run exhaust behind the rocker panels and cut a notch in the rocker in front of the rear tires to exit the body. It's all very close under there.
I plan to put steel floor pans in (So I don't need a 20 Suit) Then I'll put an aluminum floor on the bottom side of the cage tubes just between the frame rail & the rocker tube. That will give me an 1 1/2'' air gap as an insulator to keep the floor a little cooler. Sort of a heat shield for the pipes.

Thanks for the numbers, Pro... What size are your primary tubes and collectors????

Dave, they are 2.25''-2.375'' step tubes with a 4'' collector. I would have gone 5'' to give the pro charger plenty of breathing room but under car clearance is already tight with the 4''.

Thanks Pro. Thinking a 4 1/2" collector for mine, maybe the 4 into 2 into 1 stuff, too. Ran them on a 514" Ford a few years back, seemed to help the bottom end (60' times dropped half a tenth), suppose it helps a similar sized BBC the same?????

Got an email from Mike Forte, he has the shifter for the TKO's that is located 12" back of the block, which would work fine where I have the sbc mocked up now so that'll work ok on the trans. If a big block is 2" longer then a small block, the front of the block will be about 3 1/2" back of the spindle centerline as things are mocked up now.....

you can build step headers 2 1/4 to 2 3/8 but if your running a ex 4inch collector is all you will ever need i think.no need to go bigger you will have a hard time with them if your going under the floor pan. for the primary length of 36 or less but thats hard to do some times. if that trans will not take more then 600 tq i would not want to build to much bottom end

Originally Posted by pat mccarthy

you can build step headers 2 1/4 to 2 3/8 but if your running a ex 4inch collector is all you will ever need i think.no need to go bigger you will have a hard time with them if your going under the floor pan. for the primary length of 36 or less but thats hard to do some times. if that trans will not take more then 600 tq i would not want to build to much bottom end

Just spent some time this afternoon doing some measuring Pat.... No way a 3 1/2" collector would work under the car..... Looks like they're going to be outsiders..... No step needed with a 4" collector???? Kewl, less tubing to buy!!!! Should be able to lazy up the cam enough to keep the torque below 600, right????

Originally Posted by Dave Severson

Just spent some time this afternoon doing some measuring Pat.... No way a 3 1/2" collector would work under the car..... Looks like they're going to be outsiders..... No step needed with a 4" collector???? Kewl, less tubing to buy!!!! Should be able to lazy up the cam enough to keep the torque below 600, right????

well you can step them but you could just build 2 3/8 to 4 inch thats what i have done in the past if i do the big engine looking to do just a 2 3/8 i do not need the power any ways . i am getting old took my chevy out last week just a short rip down the road . i forgot how fast that thing was things pass by you faster the older you get