Hello all.

79 f150 scab 400 2bbl c6 4x4 long box. Healthy engine but I don't think any performance stuff.

Sorry for long post. Need details.

Currently has 2 rusted out cherry bombs and after 2 years, time to fix that problem. The truck has a 155" wheelbase and so does a 96 scab long box. Because they both have the same wheelbase, I'm looking to use a cat back exhaust system from a 92-96 on the 79( no cats thou). Hangers even in the same place from the jy. The 79 has 2.25" duel pipes. I will use a 2 into 1 y adaptor from duel 2.25" inlet and a single 2.5" outlet.

For reference I'm looking on summit at the
https://www.summitracing.com/parts/sum-684012/year/1995/make/ford/model/f-250.

Exhaust, Cat-Back, 3.00 inch, Passenger Side Exit, Steel, Aluminized, Ford, Pickup, 300, 302, 351, 400, 460.

This is their least expensive system. Here is my question..... "Would this setup HURT daily driving performance? Going from duel 2.25 to a 3". I think it will. If I can find a 2.5" piping, I think I should go that route. I'm not looking for a "performance" exhaust but I dont want to make it worse either. We want something with a nice town/county sound but not the drone on the interstate.. If I/we can find the right piping, we may use the black widow venom 250 muffler.

The venom has a 2.5" in/out and a duel 2.5" inlet with a single 2.5" out. Would that work better? Then use a mandrel 2.5" tail pipe.

Back to the question again, would the jump in size make things worse? Point me to some good education post.

Thanks all.

 

Not sure how much this applies to you but I just went from dual 2.5" exhaust with turbo mufflers to single 3" on my truck. Mild 351w with 2.5" pipe from the manifolds to a "y", then about 3' of 3" pipe to a large case summit turbo to a 2.5" tailpipe. The idle to 2500rpm performance greatly improved with no change at higher rpm. Also much quieter inside and out. Long ago in Hotrod magazine they built a 400hp 400 with manifolds and single 3" exhaust with a dual outlet flowmast muffler. If your engine doesn't have any performance mods you may be ok to run single 2.5", I would go with 3" with a smaller tailpipe out of the muffler. The smaller pipe will supposedly help keep exhaust velocity up as it cools on it's way out of the system

 

Am I thinking this correctly? A 3" is too large for my stock vehicle? I have googled exhaust systems but there is so much different information that I'm not sure what I should use on the truck. Everything seems to be geared to "race" cars. Not basic stock trucks.

 

I am going for 2.5 with my stock manifold 351m.
BUT I was going to go with 3 inch. I have always
read that some back pressure is good. I have also
read that too much is bad. seems 3 to 5 psi in your
exhaust tubes is good you don't want much more
than that.
the biggest bottle neck would be the stock manifolds.
I have seen in one of the hot rod magazines a 400
with stock manifolds make over 400 HP on the dyno.

on a side note.
all turbo engines made the best power across the board
with the 3 inch exhaust or larger on the dyno.

 

OP, With this being a stock 79' 400 you wouldn't need anything larger than a single 2.5" exhaust. Anything over that is overkill and hurting performance more than helping it being stock. We don't have any data confirming a later generation exhaust will fit your truck.

The only exhaust system we offer for your truck is the Hooker Headers HOK-16561HKR 2.25" dual header-back system. This system would require Hooker Competition long tube headers such as HOK-6902HKR. For keeping this a stock cruiser this route isn't necessary.

You're on the right track with a single 2.5" mandrel-bent system.

If on a budget you could keep the current system and replace the mufflers. Something like a Magnaflow or Summit muffler would provide a nice performance tone but not be too loud or raspy. We linked to 2.25" center in/out mufflers assuming the cherry bombs were the same.

 

Summitracing... Thank you for the response. I do not find on your web site any 2.5" cat back systems for the 92-96 ford supercab long box. What am I missing? Thank you. Chris.

 

Tailpipe "Tips"

Does the tip actually affect sound/tone OR is it basically eye candy? Stay with the standard 2.25/2.5" end or install a 3" tip?

I found a system that is 2.5" intermediate pipe into muffler with d/o 2.25" out. Will that affect performance going from 2.25 up to 2.5 than back down to 2.25? Or am I over thinking this? (should I stay 2.5" in/out)

Yes I'm basically stock now but would like to do minor upgrades in the next couple years so why buy the pipes twice.

Thanks to everyone for helping educate me.

 

Chris,

You're not missing anything. For those years we either offer single 3" systems like the one you found or dual 2.25" systems. We have this single 3" into dual 2.25" out SUM-684011. It has good reviews with customers liking the sound from it. We don't hear any negative feedback on it about a lack of power/performance. This is with a 300 inline-six or 302.

The same goes for that singe 3" system you found. Customers like the sound and value of it without any negative feedback about performance. Looking further into this there wouldn't be an issue going with a single 3" system or dual 2.25" if a single 2.5" system isn't available.

 

Tips can affect sound. I used to have a pair of megs cone tips on a 302. Totally changed the sound

 

Instead of trying to make another system work, why not take it to a muffler shop and have them build you something? I had a complete true dual 2.5" from the manifolds back, with dual Flowmaster Series 40's fabbed up for less than $500. Much cheaper than any kit I could find online. Shop around, shops prices will be all over the place. One place quoted $1200, another $700. 4 years later and it looks and sounds like new still.

 

I would take it to a muffler shop, Absolutely. First off, they do all the labor and the exhaust fits like it is custom fit because, ...well, it is. Second, any issues arise and you have a real person to help you out.....haven't met a computer yet that can do the work for you. Lastly, the price $$$$...time is money, why go through all the fits and hassles of putting together a "kit" exhaust that costs darn near the same as the local guys esp. when it is not welded and it is not ever bent right for any vehicle? I too have been tempted by Summit and Jegs and others but, bottom line is that they just do not fit. I found out the hard way and really, I would like to save you some money.

 

I don't mean to knock Summit or any other company. I'm finding that some of the kits they sell are pricey and you can save by supporting a local small business AND get a great, sometimes superior product.

 

Thanks to everyone that responded.

The dual 2.25" coming off the exhaust manifold are in decent shape. Im thinking a 2 in to 1 Y with a straight pipe or mandrel bent to a upgraded muffler in the stock location( or close to stock location) to a mandrel bent tail pipe. So really the only thing being used from the OBS exhaust would be the tail pipe. Am I ok using a 2.5" tail pipe with a 3" or 3.5" tip?

When this whole covid19 is done, we are hitting the road to Michigan and anything should be better than the noisy rotted out cherry bombs. But wr don't want obnoxious drone either.

Once again, thanks to everyone's input.

Chris

 

Chris,

That is a good plan of action. We don't see a problem running 2.5" after the Y to a 3" or 3.5" tip. On the muffler, we would recommend something with packing to help take down on drone/pinging. That would be a perforated stainless tube with packing style muffler like a Magnaflow. Being more of an open exhaust even with a good muffler you could still end up with drone. You may end up needing to install a resonator.