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4 banger to V8 swap

Discussion in 'Drivetrain Tech' started by Jaybo5.0, Jun 18, 2018.

  1. Jaybo5.0

    Jaybo5.0 New Member

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    I am currently rebuilding a 302 for my 88 notch. It's got a tubular k member I have motor mounts and all that but my question is, will a V8 work with the factory 4 cylinder 5 speed until I can get my hands on a WC T-5 or Tremec?
     
  2. broncojunkie

    broncojunkie Active Member

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    The t5 will work. I believe you'll need to source a fox v8 bellhousing. You'll also need a pilot bearing from an early/mid 80's ranger with diesel engine. I believe 1983 works, but you can look it up easily. The 4 cyl t5 has a pretty low 1st gear, which works great with a stock rear gear. If you were planning on swapping in a lower gear, I'd wait till you upgrade the transmission. A 4.10 is way too low and makes 1st pretty much pointless.
     
  3. broncojunkie

    broncojunkie Active Member

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    Oh, and the 4 cyl t5 from that year is still a "World Class". I'd run it till she breaks. Sometimes you get lucky and it may last years.
     
  4. Jaybo5.0

    Jaybo5.0 New Member

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    That's kinda what I was thinking, run it till I could get the one I want or one out of a GT with belhousing I will prob get a 9 inch Currie setup but only after I swap the trans. Thanks for the reply.
     
    broncojunkie likes this.
  5. broncojunkie

    broncojunkie Active Member

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    Just fair warning... you may have trouble finding a used t5 from a v8 car that isn't trashed. And not all v8 t5's are the same as far as strength is concerned. Your best bet is to get a t5 from a 94-04 v6 mustang. They have a slightly longer input shaft, which sets your shifter back about 5/8". That's a good thing, from what I've found. The fox length input shaft and bell put the shifter too far forward. Not an issue with factory shifter but causes clearance issues on most aftermarket shifters with adjustable stops. Locating the shifter back slightly also makes it easier to reach your front two shifter base bolts.

    I want to say 86-89 gt t5's are rated at 265 ft-lb. 90-95 v8 t5 rated at 300. 94-98 v6 rated at 265. 99-04 v6 rated at 300. You have about a 99% better chance of finding a good t5 from a v6 car and they are usually much cheaper because most people don't understand they can be used in v8 cars fairly easily. The 94-98 v6 t5 can be bolted right in with a 94-95 v8 bell. You can also swap in a shorter fox v8 input shaft and use a fox v8 bell...OR you can buy a spacer that allows you to use the longer input shaft with a shorter fox bell.

    The 99-04 v6 t5 is stronger, but the tailshaft housing is set up for electronic speedometer. You can swap a tailshaft housing from an older style (has to be world class but can be 4-6-8 cylinder version). You'll have to drill a small hole in the main shaft to swap in a speedo drive gear and retainer clip to work with a mechanical speedo. The shaft is hardened steel and not easily drilled, but a diamond bit on a dremel does great.

    While the tailshaft housing is off, you can add a billet steel cluster support plate for under $50. Easy upgrade that helps add strength. Another mod is to buy shim kits for both the input shaft retainer (to set end lash on the main shaft) and the cluster/ counter shaft. Shim both shafts to where there is a very slight preload. They're set up a little loose from factory.
     
  6. broncojunkie

    broncojunkie Active Member

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    Look up this guy on YouTube. He beats the tar out of t5's on the track and uses v6 and 4 cyl t5's.

    This is a video he did about t5's. Click on his other videos and see tons of racing footage.
     

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