Inliners International Forums General Discussion Hi Performance 250 buildup

I am in the process of putting together a 250ci out of a 76 Nova in a 50 StyleLine Coupe. the car is for my 16yr old son so extreme performance is not currently gonna happen. The build will consist of stock pistons, deck shaved .010, we have an earlier head style head (being the orginal was an intergrated style)that will be getting 1.94/1.5 valves, an isky 256 cam & Gears, Engine racing's 3x2bbl intake w/ 3 holley 5703 style carbs (ealy ford escort), Langdons Cast eshaust manifolds, turbo 400 trans and a 3.08 posi. In a recent discussion with someone they suggested using small pipes (max size of 1 3/4) and was wondering what others thoughts on this would be. My thought was to do 2" off of the manifolds into a y-pipe out to a 2.5" single. My experience has mostly been with SBC's, alhough a recent car I got rid of a few months ago was a 55 Plymouth with a 230 Flathead running duel carbs, reground cam and Edgy Aluminum head and duel 2" exhaust, the performance wasnt all that great and maybe in partial to the exhaust. Any help here is appreciated.

i will start and tell you to use 1.84/1.6 valves and if going bigger on the intakes use a 1.90 at the biggest.

your exhaust scheme sounds reasonable. it will sound better if you keep the 2 pipes seperated to the rear. then you will get the rap sound. tom

Thought about the duel exhaust and rap sound, but being boys will be boys and he is only 16 and I thought it might be a little better to be a little more stealthy as to not draw to much attention, I probally will still go with some type of glass pack to give a little bit of sound to it.

Running a single 2.5" to the back w/a glasspack will not be stealty,it will be loud.

I got a ticket(too loud) for a simular set-up but I had a quieter single tubo muffler,& it was not a straight through design.

MBHD

Your right, I did however mean turbo style muffler..

Awwww, dad...... Give him the pipes. If he can't be fast he ought to at least sound cool.

I don't think dad wants to pay for a ticket of being too loud.
Plus take it in for inspection, plus take time off of work & so-on. :-)


MBHD

HA HA, you are somewhat right, in the town where he goes to school there is no police, the town uses 2 other towns police depts to police the town, one of the towns put the cops that are on the chit list or rookies and the other is always out to bust the school kids, he will sit in an area that has a rediculous speed limit and on nights of school activities to pop these kids on there way home. Besides using a muffler like a Magnaflow or Borla turbo muffler will still get some sound and having a 50 Chevy Coupe with descent paint & wheels is sure gonna spell cool no matter how it sounds.

I haven't tried them on a 6 (yet) but I have good luck with (and like) the Dynomax super turbo mufflers. I have a set on my A (bent 8, bear with me).

It's cammed up enough (with some compression and a dearth of flywheel mass) that it has some lope at idle, nice melow sound (unoffensively quiet too). It doesn't get 'loud' till you are 2/3 throttle and above (it's still not that loud, and by that point sound would be the least of your concerns with the Po-lice ).

Not sure how that would work with a sigle piped 6, or even a split exhaust W/ twice pipes, but they were cheaper than either Magnaflow or Borla and have stood up to a beating, literally.

That was the same muffler I ran,,,, a single Dynomax super turbo.
It has mandrel bent tubing,an "S" bend through the muffler,no baffles,ran 2.5" single out to the back of my Camaro & got a ticket for being too loud.

I think I remember about in the old Clifford catalogs,as not to run anything bigger than 2" pipes or it will be really loud because of the 6 cyl inherrant (SP) special/different/auctive,high level of sound.

I have the old catalogs somewhere.

MBHD

I ran a set of smitties on the flathead 6 with 2" duels, it was obnoxious, swapped out the mufflers for two borla XS turbos and was very nice, had nice mellow tone idling and driving and didnt get real obnoxious when wide open. I also have the same mufflers on my 67C10 but 3" on a 427 small block pushing 550hp and I can listen to the stereo while cruisinng 65-70mph, they will also let you know I am coming if I go wide open throttle. I am also running the same 3" on my 48 with an LS1 that I ended up putting an additional cheap set of turbo mufflers for resonators to help tone it down just a tad more (should have went with 2.5").

250 w/ a head from a 194, clifford intake, holley 390, clifford dual headers and full 2" dual exhaust with glasspacks and resonator tips. It's fine when cruising, but a little gas and you can hear it blocks away. seriously, at WOT it can be heard at the police station 1/2 mile from my house.

not driving it currently but am VERY careful when I do.

considered turbo mufflers to replace the glasspacks. will reevaluate after installing the buick draw through turbo.

definitely go smaller than 2" if you go dual. with just the 194 head, stock manifolds, and single 1 7/8"(i think)w/ turbo muffler it sounded healthy.

I am going to go cutouts so I can have the Best of Both Worlds, Loud N Quiet

I'm running Langdon's cast headers on my '66 Elco/250. In the box with the headers was instuctions as to what type of glasspac[perforated core], length [36"], size tail pipes[2"].

I took the Elco to the exhaust shop with the instructions and left it. When I went to pick it up, it was LOUD. I looked under it and asked "what the length on the mufflers?" Reply: "we didn't have any 36" so we installed 30". We had a discussion about "verbal contracts" and they agreed to order a pair of 36" perforated core glasspac.

The difference was night and day. It's prety mild with no intrusion at cruise, nore do people stare at it when I drive by.