Which Engine Would You Choose?

Discussion in 'Classic Mustang Specific Tech' started by robert912005, Sep 22, 2013.


  1. robert912005

    robert912005 Member

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    cool thanks guys.... Im thinking about doing a 331 stroker... Any good kits and will it fit into my $2000 budget? I have been looking around a northern auto parts but i couldnt find any pistons that would work.... any suggestions?
    #21
  2. rbohm

    rbohm Founding Member

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    most 331 stroker kits are going to run right around $1600 on average. you might be able to find cheaper kits, i think as low as $12-1400 but remember you get what you pay for. so just the stroker kit tags your budget for 2/3s off the top. if you can find some used aftermarket heads in decent shape, and if you can do 90% of the work yourself in assembling the motor, and assuming there is no issues putting the motor together, you might be able to build a 331 for $2,000.
    #22
  3. robert912005

    robert912005 Member

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    Yeah i have rebuilt a couple of motors and have done the plasti gage with my dad... i believe i can do the assembly work just not the machining cuz no tools... i do have a degree in mechanics... Where would be a good place to start looking for a 331 stroker kit?
    #23
  4. robert912005

    robert912005 Member

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  5. woodsnake

    woodsnake Active Member

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    Plus machine work, the pistons are a 4.030 bore.. You should turn the crank too, or at least make sure it is good enough to polish.
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  6. robert912005

    robert912005 Member

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    there was a crankshaft in the link that i posted for a kit that i might start with... and yes im going to bore it 30 over
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  7. Hack

    Hack Active Member

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    If you're doing a stroker I'd go 347. I like Coast High Performance. You can get into a stroker kit for around $1700, but then you still need machining. I do think that a stroker kit is a good way to go. If you just bore, buy good pistons, put ARP bolts in the stock rods and remachine everything you will be so close to the same cost you will kick yourself. Those extra cubes are nice to have.
    #27
  8. robert912005

    robert912005 Member

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    but ive heard that a 347 will wear the engine out faster and i believe the rod pin is so high on the piston that it is in the rings... ive heard there could be problems with that setup
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  9. rbohm

    rbohm Founding Member

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    that was true in the old days when the 347 was first created, however things have changed in the intervening years, longer rods, better materials, etc. all help the longevity of the combination.
    #29
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  10. robert912005

    robert912005 Member

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    i see... thanks for the advice... now ill be doing a 347 stroker... any suggestions on what cam, rocker arms etc... would go with this setup?
    #30
  11. rbohm

    rbohm Founding Member

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    for rockers arms i recommend a full roller setup with a stock 1.6 ratio. which arms you choose is up to you, but the name brands are going to be the best ones to buy.

    as for the cam, you are going to get a lot of differing opinions on that, and most will be good ones, so to cut through the confusion now i will give you a set of guidelines to use when selecting a cam;

    1: first decide if you want a flat tappet or roller tappet cam. flat tappet cams are less expensive to buy, but you will need to use a zinc additive on a regular basis to prevent wiping a lobe down the road.

    2: decide what rpm range your engine is going to spend about 80% of its time in. dont say you want to go drag racing, when you are going to spend most of the time driving on the street. you want a cam that will work best for 80% of your driving needs

    3: once you have selected the rpm range, you can then look at cam specs, the first one to deal with is lobe separation angle compared to your static compression ratio. lets say you built your engine with a 9:1 static compression ratio, you should then look for a 110-112 lobe separation angle to pump up the dynamic compression ratio. as the static compression ratio goes up, the lobe separation angle and come down. a 10:1 compression engine can use a 108-110 lobe separation angle.

    one more thing, the narrower the lobe separation angle, the more valve overlap you have, thus the lower the dynamic compression ratio.

    4: now we can deal with lift and duration numbers. when talking about lift you also need to take into consideration coil bind on the valve springs. more lift at the valve means that you have to have coils with a taller installed height to prevent coil bind, and that means you also have to keep in mind the seat and open spring pressures.

    in regards to duration, you want to compare cams with the .050 duration numbers, as advertised duration number can be artificially pumped up by the cam makers.
    #31
  12. Hack

    Hack Active Member

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    If you're doing a street build less than 450 hp I'd buy a 302 core block from the late 80s with the provisions for roller cam. For a cam I'd recommend you call Comp and tell them everything about your application and they will select the cam and springs you need. Make sure you know all the details including rear gear, heads, approximate compression ratio, headers, exhaust, tires, weight of the car etc. You should run a cam with the late 80s HO firing pattern. If you're running a T5 you can select a stroker kit with the 50 oz imbalance so it's compatible with the 80s Mustang flywheels and harmonic balancers. Otherwise you can go 28 oz, but if running a modern over drive transmission your flywheel will cost more.

    When selecting the stroker kit and heads think about compression ratio. You'll want to run between 10:1 and 11:1 CR with aluminum heads and a performance cam. To fine tune the CR you want to run a dynamic compression calculation with the cam of your choice and you can have the block decked/select head gaskets that get you where you want to be. You can see that the various components all feed into each other, so it can be an iterative process if you're a bit of a perfectionist like me.
    #32
  13. robert912005

    robert912005 Member

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