First Time Builder- What Can I Expect?

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Jim Pawloski, May 6, 2014.


  1. Jim Pawloski

    Jim Pawloski Member

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    So I picked up a 65 with a a little 289 in it. I plan on starting the engine rebuild here soon and was hoping you experienced guys can tell me what type of horsepower I could realistically obtain. I plan on stroking it to 347 and upgrading to a 4brl carb. I'm also a huge fan of boost and was thinking about getting a Paxton supercharger to keep everything under the stock hood. Without the cost of the charger ($4300), what do you think the grand total would be? Horsepower and torque? Is about 500 at the flywheel a crazy number or what? I really have no idea what to expect out of this build. What are your guy's recommendations?
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  2. Busamike

    Busamike New Member

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    with a good 347 you should get around 400 hp. With the sc, push that to 500ish. Must run forged internals with an sc though, unless you keep the boost down to 5 psi or so and at that if youre stepping on it it may come unglued. Youll have to keep the compression low also, under 9 to 1. stay in the mid 8s to play it safe.To do it right, with a forged rotating assy short block, probably 5k.. just a guestimation. HP aint cheap. Im running a 347 stroker in my 65 and it was about 10k for the crate. I built the 383 stroker in my C-10 and am running a 177 ci roots sc on it. about 10k for all. so there you have it.
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  3. rbohm

    rbohm Founding Member

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    keep the compression ratio right around 9:1 and run no more than 6psi boost, and with the right heads, cam, headers, etc. you can reach the 500hp flywheel goal. the tuning is going to be the key.

    that said my advice is to forget the supercharger right now. build the engine, with 9:1 compression, and get it tuned right and drive it for a while and get a feel for it. then down the road drop on the supercharger.
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  4. robert912005

    robert912005 Member

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    hey are you planning on stroking a 302 to a 347? I believe you cant stroke a 289.
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  5. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Sure you can
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  6. Jim Pawloski

    Jim Pawloski Member

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    Thanks for the info guys. The charger I was thinking about going with is the Novi 1200 from Paxton, and their site is saying it's putting out 7.5psi. With forged internals is that too much?
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  7. Jim Pawloski

    Jim Pawloski Member

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    "that said my advice is to forget the supercharger right now. build the engine, with 9:1 compression, and get it tuned right and drive it for a while and get a feel for it. then down the road drop on the supercharger."

    This was my plan, the super charger would be added on much later, but I planned on building the engine for it when I have the money.
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  8. rbohm

    rbohm Founding Member

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    7.5 is fine. just remember to get tight controls on your A/F ratios when you supercharge the engine, and add some kind of boost retard function. as long as you control detonation, you are good to go.
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  9. Jim Pawloski

    Jim Pawloski Member

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    "Boost retard function" Is that a blow off valve?
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  10. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    You can expect to beg, borrow, or buy, a bunch of tools that you may or may not have. hehe
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  11. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    No, what he is referring to is a devicethat will tell the computer to retard the ignition timing when its starts seeing boost.
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  12. rbohm

    rbohm Founding Member

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    that is one way to retard ignition timing, assuming you have that ability with the electronic ignition system you choose to use. another way with old ford distributors is to use a vacuum advance unit that has a vacuum retard function built in, you can usually find them in california emission package distributors, and hook the can up to a point where it will not only see vacuum, but boost pressure as well. when the boost comes on, the ignition timing will start to retard automatically.
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  13. Jim Pawloski

    Jim Pawloski Member

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    Yeah, I don't have an electronic ignition, it's using a distributor. Any recommendations?
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  14. rbohm

    rbohm Founding Member

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    yes, get a duraspark distributor with the california emissions package. it has a diaphragm that has two vacuum ports on it, one for normal vacuum advance, and one for vacuum retard. leave the vacuum retard port open, and hook the vacuum advance port downstream of the supercharger. that way when the boost comes on, the pressure will retard the timing as boost increases.
    #14
  15. iskwezm

    iskwezm Advanced Member

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    I had a SN2000 Paxton for a while on my 289 then built a 347 with a turbo. You will need a better fuel system and carburetor with the blower. I think had about $1700 in the carb and pump regulator/lines and fittings.most of it sitting on a shelf now
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  16. Jim Pawloski

    Jim Pawloski Member

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    Yeah, I planned on getting a Holley double pumper with an in-tank electric fuel pump. Would this be sufficient?

    Sweet, Thanks for the info. This is going to be my first engine with boost, I would have completely overlooked this.
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  17. iskwezm

    iskwezm Advanced Member

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    basically you need a pump that will put out 1 lb. of pressure per pound of boost and have a boost referenced regulator. My pump would free flow up to 28psi and 310 gph. So if your carb already needs 6-7 psi add in the 7-10 psi/lbs. for the blower, that's 13-17+ lbs. of fuel pressure and the stock fuel line will not be able to flow that. The carb has to be set up for a blow through application, a off the shelf Holley will not do. I have over $850 in my carb alone, and another $500 in the pump and another $400 in -10(1/2") line and fittings.

    make sure its really what you want to do, it will all add up quickly to do it right.
    #17
  18. RacerJames

    RacerJames Member

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    So, wouldn't electronic fuel injection be a better option with boost? I've always admired the boosted stuff from afar. One day I thought I might build one...
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  19. rbohm

    rbohm Founding Member

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    yes EFI would be better, but even still you would want a boost referenced regulator to up the fuel pressure under boost. regardless of whether you use a carb or EFI, or even mechanical fuel injection, you are going to need to get more fuel in during boosted phases than non boosted phases.
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  20. hipo_p51

    hipo_p51 Member

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    These things are money pits. I would just forget the sc or turbo idea. You can build a serious motor with just a carburetor on the top. Keep it simple and the car will be more enjoyable. my 331 with a Holley HP carb makes 470hp to the rear wheels at 7700 RPM. yes its a lot of rpm's, but it is built accordingly and easy to keep tuned. however like a said, 'money pits', that 470hp did not come cheap. just my .02 cents.
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