I am looking in to buying a 383 crate motor and it is rated at 420 hp will A TPI support it? I have a ported plenum, and plan to upgrade to bigger injectors. Any one have any other thoughts?

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flowmaster,afpr,coolant by-pass,ex.cutout,ported plenum,hyp.chip,cold air intake,airfoil,mod.maf
160 thermostat,hyp tech fan switch, B&M shift Kit,

 

A ported plenum with a bigger throttle body and fuel injectors will support it. Plus the other things such as bigger tube runners and manifold base, you shouldnt have a problem.

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88 GTA
L98 350
700R4
3:27 axle
MODS,
Edelbrock TES headers, 3" straight pipe, Flowmaster 80 series, K&N filter, Accel 8.8mm wires, Bosch Platinum plugs, Wells cap and rotor button, Wells ignition module, MAF screens removed, Hypertech TB air foil, Thermomaster stage II chip, 180* Powerstat, Hypertech cool fan switch, B&M shift kit, B&M power clutch pack, B&M servo, GM fuel filter.

 

Large tube runners and a heavily ported or aftermarket manifold will be essential. The stock pieces will choke a 383 built to make 420 horsepower.

 

A general rule of thumb is that a modified TPI system can support 1 hp for every cubic inch. This rule should only be used as a guide.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

You will need a Superram manifold to achieve the 420 hp advertised. Your stock tpi will choke your 383 to the point peak HP will only occur at around 4300 rpm, with a result of around 350 hp.

A tpi with aftermarket manifold and aftermarket runners will let the motor breath up to around 4700 rpm... however you will still only be around 380 hp give or take a little at that rpm.

A Superram will allow the 383 to run quite a bit higher and tpically your peak HP will occur around 5300-5500 rpm with the appropriate cam and good flowing heads. This set-up will make the advertised 420 and probably another 10-20 hp on top of that, with a strong torque curve starting as low as 2500 rpm.

Have a look at my webpage in my signature for some of my experiences and opinions on making power with a tuned port motor. Go to the "My Set-up & Results" section.

Hope this kinda helps.
Todd


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85 Vette
SR 383 Motor
11.67 @ 116
http://corvetteforum.net/c4/beach_bum/