How much will these headers hurt my small block?

Posted By: flatlinedude

How much will these headers hurt my small block? - 08/13/09 03:30 AM

Stock magnum 360 long block, cam and all. Dual plane intake, carter 750, thats all thats done to it. In an a body with a 28" tire and 4.10 gear. I have 1 5/8" hooker comps on it now and it runs good, but the headers are about shot. I have a set of tubular automotive 1 7/8 x 3.5" headers that I'd like to set-up and use. I know the combo is all sorts of wrong, but will it make that much of a noticeable different from the smaller tubes?

I eventually plan on doing a head and cam upgrade. Thanks.

Posted By: S/ST 3040

Re: How much will these headers hurt my small block? - 08/13/09 03:41 AM

You'll have to turn a 360 pretty hard to get any benefit from a 1 7/8" tube.
Even then, 3" collector would be better than 3 1/2".

Posted By: 383man

Re: How much will these headers hurt my small block? - 08/13/09 04:12 AM

I agree as I only use 1-3/4 tube headers on the 440 in my mid 11 second 63. I would suspect you will loose some low end and will not make it up on the other end with your combo right now. Ron

Posted By: flatlinedude

Re: How much will these headers hurt my small block? - 08/13/09 04:47 AM

I know they are far from optimal, but about how much power loss are we talking? This motor currently is all in by 5k... lol dang deisel.

Another header question, will the slip fit tubes be leaky if used with an actual exhaust? Seems like they very well could with the back pressure... ?

Posted By: MR_P_BODY

Re: How much will these headers hurt my small block? - 08/13/09 04:52 AM

Quote:

I know they are far from optimal, but about how much power loss are we talking? This motor currently is all in by 5k... lol dang deisel.

Another header question, will the slip fit tubes be leaky if used with an actual exhaust? Seems like they very well could with the back pressure... ?

Hard to say how much power you would loose... on the
slip fit, they are pretty decent fit(or they should be)
and after a short time they tend to seal up even better
(rust and or carbon)

Posted By: qwkmopardan

Re: How much will these headers hurt my small block? - 08/13/09 06:35 AM

With a restrictive exhaust syatem it probably won't effect it much at all. If you were talking open headers I would expect some low end laziness which could be cured by putting a 2 1/2" street hook-up reducer on them.

I would expect some minor leakage around the slip fit joints, and as Mr P said the longer they are together the better they should seal.

Posted By: flatlinedude

Re: How much will these headers hurt my small block? - 08/13/09 02:35 PM

Is it common practice to use any type of sealer or anything on these type of joints?

The exhaust is just 2.5" w/ chambered mufflers dumped at the axle.

Posted By: 1Fast340

Re: How much will these headers hurt my small block? - 08/13/09 04:10 PM

Quote:

Is it common practice to use any type of sealer or anything on these type of joints?

The exhaust is just 2.5" w/ chambered mufflers dumped at the axle.

i never used any sealer on the slipjoint on my TTI headers and they have been sealing up perfectly, this was with 3" exhaust and some diferent mufflers but no problems keeping it sealed!

Posted By: BobR

Re: How much will these headers hurt my small block? - 08/13/09 04:13 PM

Quote:

Is it common practice to use any type of sealer or anything on these type of joints?

The exhaust is just 2.5" w/ chambered mufflers dumped at the axle.

Chambered mufflers cause back pressure and therefore may cause your slipjoints to leak. I would toss those in favor of a good flowthrough muffler.

Posted By: flatlinedude

Re: How much will these headers hurt my small block? - 08/13/09 08:29 PM

Thanks guys. Just trying to work with what I've got. Thanks again.