I'm getting ready to build my hotside for my 4.9 litre V8. Ive got a couple ideas, being a Ra-Tard to all things Turbo I thought it might be best to ask first.

Option 1) modify a set of Shorty headers to use them in a forward facing manner with a crossover pipe connecting them bear the turbocharger. The headers are 1.5" primary tubes with 2.5" collectors. That would put the crossover at 2.5".

Option 2) build a setup similar to the Grand National system where the crossover goes under the engine and joins the passenger side header at the rear. I could still do 1.5" primary tubes and go with a 2.25" crossover.

#ad
#ad

 

If it was me, I would do shortys forward facing.
Spool will be faster and the passenger side of the engine wont suffer from double the exhaust volume on its side.

 

I think I may look into doing twins as it will be easier to get the downpipes in the small space available on each side of the engine and it's less Hot side piping to mess with. I'll have to research the advantages and disadvantages of twins versus single.

 

I am selling some twins off my car ($750/pr). They were custom built for my application and have polished housings and billet wheels but I don't know all the internals.

They are 60mm and produced 950RWHP (approx 1100FWHP) at 39psi (840RWHP at 18psi) on my 2V mod motor Mustang. They are listed on FB right now.

If interested PM me and I can try and give you more details so you can research to see if they may work for your application.

KS

 

Forcefed used to say that he would run a 2” crossover on his 4.8 and 5.3 builds, claimed that 2” would support 1000hp if memory serves. I am running 2.25” divided hot side but that is with 395 ci.
Just run a reducer from the header to whatever size you decide on. Just because you have a 2.5” collector doesn’t mean you can’t be smaller on the crossover.