Forced Induction Thinking Of Turbo Charging My 77 302

Jermy

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Jul 16, 2015
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Duncan, AZ
Im currently thinking about turbo charging my Cobra ii and was wandering if anyone had any ideas on the type and brand of turbo I should go with. Im putting in a Edelbrock Pro Flo 2 EFI System, Performer Hydraulic cam and lifters and Performer RPM Heads. I want to keep a street application, I was thinking around 450-500 HP. Any info on this would be greatly appreciated.
 
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Well... there's a ton of information out there for turbocharging the 5.0 in Fox and SN95's, and the turbo concepts, brands, and sizes will all apply to you. Where of course things will get challenging is shoe-horning that stuff into the engine bay - there's not a whole lot of room in case you haven't noticed. And of course all of the hot-side will require custom fabrication in a II so you'll either need welding skills or some serious $$$.

If you're planning on 450-500 hp, you'll probably want an aftermarket block (that's getting close to the limits of the stock block). I assume you've also toughened up the bottom end -- you don't mention what engine you're running but I hope it's a 5.0HO and not the old 70's era low-compression boat-anchor 302. You'll also need to thoroughly rework the rest of the drivetrain to support that much power. The RAD4 or stock C4 isn't going to cut it, neither is a T5. You're also going to need a new rear-end, 500 hp exceeds the old 8". Not to mention the suspension and frame reinforcement required.

Long story short, you'd be planning a huge project, probably in the >$10k range. I don't think bits and pieces of advice are going to be enough, including mine. I've turbo'd my '95, and I've also turbo'd my '78 v6, and personally I don't think the II is up to that level of modification while still keeping it a street application. I think you'd be far better off picking up a Fox or SN95 and grabbing an off the shelf turbo kit.
 
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Well... there's a ton of information out there for turbocharging the 5.0 in Fox and SN95's, and the turbo concepts, brands, and sizes will all apply to you. Where of course things will get challenging is shoe-horning that stuff into the engine bay - there's not a whole lot of room in case you haven't noticed. And of course all of the hot-side will require custom fabrication in a II so you'll either need welding skills or some serious $$$.

If you're planning on 450-500 hp, you'll probably want an aftermarket block (that's getting close to the limits of the stock block). I assume you've also toughened up the bottom end -- you don't mention what engine you're running but I hope it's a 5.0HO and not the old 70's era low-compression boat-anchor 302. You'll also need to thoroughly rework the rest of the drivetrain to support that much power. The RAD4 or stock C4 isn't going to cut it, neither is a T5. You're also going to need a new rear-end, 500 hp exceeds the old 8". Not to mention the suspension and frame reinforcement required.

Long story short, you'd be planning a huge project, probably in the >$10k range. I don't think bits and pieces of advice are going to be enough, including mine. I've turbo'd my '95, and I've also turbo'd my '78 v6, and personally I don't think the II is up to that level of modification while still keeping it a street application. I think you'd be far better off picking up a Fox or SN95 and grabbing an off the shelf turbo kit.


Hey bro thanks for the info, I was going to use the stock block but now maybe not so much. I am going to stick with the 77 but I will probably skip the turbo charger, 10k is my budget for the whole build. I will lower my expectations to around 400 hp and overhaul the suspension. If you could got any thoughts on a good suspension kit I wouldn't turn down the advice. Im sure you already guessed it but im kind of new to building a car, thanks again for the help.
 
You're welcomed my friend. Unfortunately for the II there aren't that many "kits" of any kind. You can pick up a general poly-bushing kit in a few places, as well as tubular control arms if you're interested. Most of what you'll find are II suspension kits made for grafting onto first-gen Mustangs, which aren't necessarily able to swap with the stock suspension parts.

Probably one of the biggest enhancements you can make is a set of subframe connectors to keep the car from twisting under load. After that, definitely going to 5-lugs and adding some substantial rubber on all 4 corners. Replace worn springs / shocks, and the stock suspension with some new bushings and some subframe connectors is pretty darned good. Beyond that, when it comes to the II, little is bolt-on (just about everything requires some fabrication). I don't mind that because I like to fabricate, but that's why I lean towards keeping two Mustang myself. The II just for giggles, and enjoying it for what it is, while an SN95 or Fox (plentiful and cheap) is easy to infinitely upgrade with bolt-ons and available kits. Not that it can't be done, but it's usually going to be double or triple the cost and effort of upgrading.
 
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The old 302 blocks high nickel content, this makes them stronger than the 90s blocks. His 70s block is better than the xxx block. 28oz flywheel is better anyway. Now a c4 will handle some serious abuse we launch our fox at 5500rpm with a 250shot of nitrous on a c4 weekly at the track. Albeit it is a worked over c4 they are cheap to beef up. This car is also 4 lug I have never seen a 4 lug fail at any power level, we run low 6s in the 8th........ the 8 inch rear well uhh probably need a new one.
 
The old 302 blocks high nickel content, this makes them stronger than the 90s blocks. His 70s block is better than the xxx block. 28oz flywheel is better anyway. Now a c4 will handle some serious abuse we launch our fox at 5500rpm with a 250shot of nitrous on a c4 weekly at the track. Albeit it is a worked over c4 they are cheap to beef up. This car is also 4 lug I have never seen a 4 lug fail at any power level, we run low 6s in the 8th........ the 8 inch rear well uhh probably need a new one.

The higher nickel content, from what I've read, was only present from the mid 60's to the early 70's. This likely doesn't apply to the II engine -- this sure as heck wasn't a 135hp engine using a Boss 302 block. Even if it were true, personally I wouldn't stuff a nice bottom end into a stock 302 block, since the slightly stronger material doesn't address the fundamental casting weaknesses. Besides, my primary criticism of the II-era 302 is the strength of the internals, and the rock-bottom compression ratio.

I agree that 28 oz is better, though it doesn't have much to do with the flywheel, but rather the crank. The II has a special small flywheel, so options are limited.

The c4 can absolutely be built to handle a lot of power. Where you're again limited in a II is using the smaller bellhousing, torque converter, and flywheel required to fit in the tunnel. There are limited performance options there that you didn't experience in the Fox application.

The 4-lug is probably good enough for plenty of power, where it lacks is decent wheel selection that will fit the unique backspacing required by the II. The 8" is a decent rear, but yeah an upgrade is good.
 
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I appreciate all the feed back on this. Im going to stick it out with the 77. It was the first car my dad and I bought and I promised him I would do something with it. Im starting the build in February and will post pics as I go along. Thanks again fellas for the help.
 
That's awesome, and I hope you don't get me wrong, I love my II and I wish you all the best. I was just hoping to give you some realistic expectations that you'll hit some bumps along the way and probably have to do some fabrication, it's not as easy as a Fox to upgrade. But it's well worth it in the end, everywhere I go it's a conversation piece, and the guys who know these cars know just how much effort it took to make them awesome (what's the fun in bolt-ons anyways?). A great community to check out for help along the way (lots of II-obsessed guys who know every last nut & bolt of those cars) is at mustangii.net (the forums are down at the moment but they have an active Facebook group, linked from their home page).
 
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An excellent source for suspension parts is Free Shipping @ Speedway Motors, The Racing and Rodding Specialists .
A lot of what they have is geared towards the hot rod and circle track crowd, but there's a surprising amount of stock replacement and stock-compatible parts in their inventory, and their brake kits for the II suspension look impressive, I'm considering going 5-lug just to get them.

As far as a turbo in a II, I gave it a lot of thought when I had a pair of T3/T4 hybrid turbos fall into my lap a few years back, and just about the only place I could figure to put them was directly in front of the rear axles where I have my mufflers, and that would have required a lot of plumbing for oil and water lines to and from those turbos, as well as a big pipe for the compressed air back to the engine, so I decided not to go that route. I'd also played with the idea of mounting them below the trunk and switching to a trunk-mounted fuel cell, or using a set of flipped shorty headers and running no hood with the turbos mounted high and up front. There just wasn't a way to package a turbo setup in the car that I liked, had the money and skills to do, and was going to be easy to live with on the street.