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Discussion Starter #1
Hello from Alaska!

I have a 1987 Jeep J20 I want to swap a Chevy engine into. It's going to be my daily driver and tow rig for my race jeep. I want to build a small block or buy a ZZ502 from GM. Either engine will be backed by a 700r4 from Monster. Truck is and will remain 4x4. I built the engine in my other Jeep. It's a high compression straight 6 stroker, worked over aluminum head, custom solid cam, open header 4000 lbs trail ready. I put a lot of work into it and it MIGHT make 350 hp/350+ lb ft

So I have always wanted a big block, but they're fairly expensive. And I can get great power from a small block with less weight and fuel consumption is what I'm thinking.

My goal is driveability and TQ. Seems crazy, but as "trick" as a 427 SBC is, it would appear I can build it for less than a ZZ502 crate engine (But damn that 502 is already making 500+ lb ft at 2500 rpm)

I'd like to make 500 lb ft and this is not a normal 427 SBC idea. I don't want a huge cam or heads. I am thinking along the lines of AFR 195 CC heads, ported 2.5" outlet ram horn exhaust manifolds and a dual plane intake. Planning to run a carb.

Reason for manifolds and not headers is it will make the swap easier into the truck, and I'm shooting for a nice quiet engine and ride. With the solid cam in the race jeep I know I for sure want a hydraulic roller in this engine. And I only want to spin this thing as high as 6k (but maybe not even that much as I just don't need to)

What heads and cam would you guys recommend? Can this be done the way I've laid it out? 383's with iron vortec heads can make 450 lb ft, with more displacement and a little more cylinder head/cam it ought to be easy right?
 

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Discussion Starter #2
I meant to add......My other concern with the TQ of the big block is it might actually get annoying roasting the tires. I run a 265/75R16 all around and am looking at running a wider tire and the rear axle has a LS. Although this hypothetical engine would probably do the same, it won't make quite as much TQ as soon. And I'll be daily driving this. I inherited a C6 ZO6 when my Dad died and while it was fun, I spun the tires a lot and it's fairly annoying to have a ton of power and not be able to use it well. Same reason I liked my 600cc sport bike over my 750. I could be crazy though
 

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My suggestion is to build an EFI 496 big block from good collected parts. It will have way more toque at lower rpms for towing than a fairly expensive 427 small block build.
Hydraulic roller cam for sure, oval port aluminum heads (keep the weight down), 9.5. to 1 compression for 91 octane fuel, dual plane EFI intake with throttle body injection like FiTech or Holley Sniper. Self learn tuning and run smooth and lean with 02 sensors for better mileage and great towing. Keep HP at about 500-525 and make as much torque as you can from 1800-4000rpms. Race the race Jeep and not the Tow Jeep! JMHO ;)
 

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I second the 427 SB build will be expensive - you won't be using any shelf parts for the short block. I'd recommend the EFI setup as well, but with boost. A 6.0 with an LSA blower is beyond reliable and can be extremely driveable with all of the punch needed to to hit your 500 ft/lb goal with mild boost and cam.

You're worried about too much power(??) WTF????
 

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Discussion Starter #6
Will your jeep drivetrain support the unending torque of a BBC?
It's a 3/4 ton truck with a full float dana 60 rear. And like I said I'll order a 700R4 from Monster.

I like the idea of the EFI 496 or blown LS. Whatever I run I need to fit under the stock hood of the truck. For anyone not familiar the full size Jeeps are all essentially the same. The more common one is the Grand Wagoneer, my truck is just a regular cab long bed pickup version.
 

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And like I said I'll order a 700R4 from Monster.
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Bad choice, both in the source and in the trans itself....a 700R4 will never hold to that kind of power for long, no matter who builds it.

Go to the 4L80E, and if you don't want to get a electronic controller for it then go "brain dead" manual valvebody on it.
 

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Discussion Starter #8
Bad choice, both in the source and in the trans itself....a 700R4 will never hold to that kind of power for long, no matter who builds it.

Go to the 4L80E, and if you don't want to get a electronic controller for it then go "brain dead" manual valvebody on it.
Through some research this seems like a legitimate statement. How can monster build a 700R4 and rate it at 600 lb ft? Did I miss the fine print that says "in a vehicle weighing less than a 1000 lbs"?
 

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I like the LS idea also. Would easily make the power you’re wanting and be very reliable and get better mileage for a daily driver than a big block. I like carbs for racing but I think daily driver I would have to make it fuel injected.
 

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Regardless of engine, the 700r4 is going to be the weakest link. Go with a properly built 400 turbo and the trans will be the last think you'll need to worry about.
 

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The first version of my 427ci SBC that was in my Jeep made peak (593)[email protected],000, and was making 568 lb ft of torque at 4,500. Peak torque was [email protected],800RPM. Dyno started reading at 4,500 so I have no clue what it made lower.
This was a small cam, old Brodix -11X heads, and built for 93 octane.
 

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Discussion Starter #13
Nice. Thanks for the replies fellas

I don't want a 3 speed auto like the T400. I want OD and lockup.

I actually searched "torque monster" in google and that thread did not come up haha.

If a 383 can make 450 lb ft at a reasonable rpm I can't see why you wouldn't make considerably more TQ with an additional 44 cubes
 

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Yea, I know there are other variables, but...
I went from a solid roller 383 with AFR 195's, to a solid roller 427 with Brodix -11X's. Nothing super fancy, no outrageous lift on either cam. The difference in TQ was amazing.
Ran 4.6's in the sand (300') with the 383 and a 150 shot of nitrous. Went 4.5's N/A with the 427. No other changes.
 

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BTCurp
The mild 496 build I described at 500-525hP would have about 500-550 lb/ft of torque at about 4000 rpms, not a monster! A well rebuilt 4L80 trans with a towing converter will easily handle that. Done a lot of this same truck/towing builds and they work beautifully! Stop listening to exotic and keep it plain vanilla, it's a TOWING TRUCK! JMHO
 

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Discussion Starter #18
BTCurp
The mild 496 build I described at 500-525hP would have about 500-550 lb/ft of torque at about 4000 rpms, not a monster! A well rebuilt 4L80 trans with a towing converter will easily handle that. Done a lot of this same truck/towing builds and they work beautifully! Stop listening to exotic and keep it plain vanilla, it's a TOWING TRUCK! JMHO
If I wanted AFR heads would you suggest 290's? Seems like the only thing smaller at 265cc would be too small? Sure it would make great TQ though?
 

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Don't spend that kind of coin on the AFR 290 oval ports for what you are doing.

Buy a set of the Flo-Tek 290 /112cc chamberl port aluminum heads with a simple 2.25I-1.88E valves and a hydraulic roller spring package for max .650 lift cam and your good to go! These heads flow about 360cfm and thats way plenty for what you need to do. About 1/2 the cost of the AFR's and about 95% as good.

Use the savings to buy a nice set of Tri-Y 1-7/8" stainless long tube headers!-Torque!;)

www.flotekheads.com
 

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Bad choice, both in the source and in the trans itself....a 700R4 will never hold to that kind of power for long, no matter who builds it.

Go to the 4L80E, and if you don't want to get a electronic controller for it then go "brain dead" manual valvebody on it.
What's the cost of a 4L80e swap these days? In the SyTy world, it's a bit of a swap with AWD, needing a xfer case adapter custom made and other parts, too. They spent upwards of $4k or more most times. That doesn't make it a viable swap for a lot of people. What's the process for swapping one into a J20 3/4 ton truck? Do they have avaliable adapters for the jeep xfer case, etc? Will it handle that sort of power? What I'm seeing says no. In that case you're gonna be looking for something better to replace it, right.
 
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