stroker questions

[cargs]

I'm looking at picking up a 1996 explorer v8 AWD for a swap in my truck. the explorer has 280,000km on it, so the engine would likely be ready for a rebuild. For the cost of a rebuild and machine work to the block, i was thinking it may be more cost effective to pickup a stroker short block and put the remaining stuff from the explorer v8 on it. (sell the explorer short block).

1. What kind of hp and torque numbers could one expect from a explorer v8 stroked to ~347 with the gt40 heads and intake etc.?

2. Are there any issues with the stock computer and a stroked engine?

3. What kind of pistons should be used, flat or domed?

4. Are all the 302 blocks the same? will all the accessories from the explorer bolt up to any 302 block?

Thanks!


* Sorry if any of these questions seem ignorant, but everyone has to learn.

** I realize all the wiring differences between a 1996 explorer and a 1993 ranger, i have the EVTM for both. I am still in the feasibility stage of the project!

 

[Gotta_gofast]

The GT40P heads are not a good choice for a stroker small block. They'll choke a 347 pretty bad. Also, most 347 ci kits push the piston pin up into the oil ring which has been known accelerate oil consumption. My advice is to look into a .25" stroker crank for a displacement of 331ci and use the roller cam block from the explorer. I'm not sure how much a shop would want to rebuild the engine for you, as I've always built them myself, but machining the block, clearancing the block for the crank, and balancing/blueprinting cost me $700.

If you're on a budget, take those 'P heads and work them over with a die grinder. Smooth any rough surfaces and blend the bowls. If you stick to basic polishing (not porting) and a performance 5 angle valve job, this will help the flow at low valve lift. Run those while you work out the rest of the bugs on your new powerplant, and when cash is sufficient step up to some AFR 165cc heads.


Now for your questions...

1. 347ci with stock explorer cam/intake/polished heads you're looking at a decent trail truck as you'll have an easy 300 lb/ft of torque along with an honest 250 hp.

2. Your stock computer will work fine, but you will need to have it tuned by a professional.

3. Depends on the type of fuel you plan to run. If you want to run 87-89 octane, I would shoot for 9.0:1 ratio if you keep the 'P heads. If you have the budget for aluminum heads, you will be fine with 10.0:1 ratio.

4. If you choose to purchase a different block, I HIGHLY recommend finding a block casted for a roller camshaft. There are numerous reasons for this. And your accessories will bolt up to any roller block.

 

[V8 Level II]

Are there any issues with the stock computer and a stroked engine?

Here's the first possible problem:

Many stroker kits specify 28.2oz imbalance as used on early 302's. From the factory, Explorer 5.0's have a 50oz imbalance flywheel/flexplate and a 36oz imbalance harmonic balancer. Swapping the engine to a 28.2oz flywheel/flexplate is a piece of cake, dealing with the harmonic balancer not so easy.

The Explorer PCM requires the special Ex 5.0 harmonic balancer because it has a toothwheel pressed on for the crank position sensor. If you simpy bolt on a 28.2oz HB from an earlier 302, it will not run with the Ex PCM.

A few stroker kits advertise 28.2oz or 50oz compatibility. That may be true but they could also be assuming the use of heavy metal slugs which adds to the cost of the balance work. It pays to ask a lot of questions up front.

And the second:

The Ex PCM has the reputation of being more intolerant of major engine tweaks than a Mustang PCM for example. The Ex 5.0 is a mass air system, but apparently the calibration is not as flexible. For example, Ford Racing recommends against using even its mildest "alphabet" cams in this engine.

You might be able to overcome this with a small increase in injector size and still use the factory PCM. The real fix is a dyno tune resulting in a custom PCM calibration. If you decide to use a Mustang mass air PCM with the Ex engine instead, you would need to convert from coilpacks to distributor and do some rewiring.

 

[cargs]

thanks for all the info. i was wondering about the balancer too.

i think that the engine will get a standard rebuild and bored out a bit; 20 or 30 over depending on what condition it is in.

what hp/tq does the explorer 5.0L in stock form?

thanks again.

 

[t_dickie]

I had a 302 block punched out .030, but not clearanced for a stroker kit (yet) and it cost me $150 at Piston Ring. Without seeing your engine, I'd guess .030 would likely clean it up.

I can't comment on the fuel injection questions, I'm going carbed. But between my aluminum heads, stroker kit (331), cam, etc. I'm expecting close to 400hp. As for a stock 5.0, I'm going to guess they were around 200hp & 295ft/lb. I'm basing that on the 351 in my '94 F-150 was 215hp/315ft/lb.

 

[baddad457]

I'm looking at picking up a 1996 explorer v8 AWD for a swap in my truck. the explorer has 280,000km on it, so the engine would likely be ready for a rebuild. For the cost of a rebuild and machine work to the block, i was thinking it may be more cost effective to pickup a stroker short block and put the remaining stuff from the explorer v8 on it. (sell the explorer short block).

1. What kind of hp and torque numbers could one expect from a explorer v8 stroked to ~347 with the gt40 heads and intake etc.?

2. Are there any issues with the stock computer and a stroked engine?

3. What kind of pistons should be used, flat or domed?

4. Are all the 302 blocks the same? will all the accessories from the explorer bolt up to any 302 block?

Thanks!


* Sorry if any of these questions seem ignorant, but everyone has to learn.

** I realize all the wiring differences between a 1996 explorer and a 1993 ranger, i have the EVTM for both. I am still in the feasibility stage of the project!

What you'll end up with will be basically a Lighting 351 in a smaller package. The GT40P's will not choke it. They will just serve to move the powerband down to a more useful rpm range vs a 347 with "bigger" heads. Bigger is not always better. It all depends on where you want the power to be made at in the rpm range. Go for it.

 

[baddad457]

And you can buy stroker 347's balanced to 50 oz/in, you'll just have to look a bit harder to find one. But even so, the Explorer balancer and flexplate can easily be rebalanced to 28 oz/in. All that's involved is the removal of some of the counterweight material. Any competant engine balancer can do this operation.