I was wondering if any one can help me? My truck has 193,213 miles on it and I plan to celebrate Y2K with a possible engine rebuild. I want some thing that will get her screaming and I believe I've found it-summit is offering in its new products section an engine rebuild kit to go from a 302 to a stroked 347.If I do this,I plan on changing the cam to a motorsport E303. How will my computer react to this? I'm not chipped but if it helps I will do so. Also-how do ya'll feel about this setup with a GT40 intake and larger throttle body? ANY input (good/bad) would be appreciated.

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92flareside 302-5speed
k&nfilter,march underdrive pulleys,flex-a-lite fan,heddman headers w/ true dual exhaust

 

I don't believe you can bore a 302 past .360. You may consider building a 351 instead? I agree with nomo, your computer will give you fits. I have heard that aftermarket cams don't always cooperate with the computer either.

 

The ECU will most likely experience a "Y2K celebration" attack.

From what I've read (not experienced), the speed-density computer system can really have problems with major mods. It is a 100% sure-bet that you will need a chip. However, this chip will have to be custom "burned" for your specific mods. It might be cheaper and easier to get a mass-air conversion kit for your truck.

Neal

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1997 4x4 Expedition- 4.6L, true dual exhaust w/glass-packs, K&N air filter, SuperChip, airbox mods, Edelbrock shocks, 285/75R16 BFG ATs, Optima "T-Bone" wheels, and Clarion In-dash CD player. Just added Smitty Bilt push bars and nerf bars!!

1993 4x2 F150 Reg. Cab LWB- 5.0L, cat-back dual exhaust w/glass-packs, K&N air filter, Superchip, fresh paint, and Line-X bedliner.

2000"other"
http://members.visualcities.com/NoMo

 

thanks for the input fellas.I think that I'll come out cheaper just to rebuild it and add a vortec or paxon supercharger along with a chip. My checkbook (wife) seems to agree.Pastmaster-I agree on the boring spec.-I personally wouldn't go over.030,the crank that comes with the kit is a 3.40" that is where the difference would come.I could be wrong though. thanks again and I'll keep ya'll posted





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92flareside 302-5speed
k&nfilter,march underdrive pulleys,flex-a-lite fan,heddman headers w/ true dual exhaust

 

Nomad: there was a guy that had a 79, that wanted to bore his 302 that far, and the guys over at told him that the cylinders would be bored to much, cylinders metal would be like paper. The engine wouldn't last at all. You might consider getting a rebuild with a warantee. And the blower is an excellent idea. You would get close to the same results with your blower, and chip, and free breathing exhuast. I think someday I will rebuild my 302, and replace it with a built 302, and I plan on replacing the Efi with a 4-barrel.

[This message has been edited by Pastmaster (edited 03-05-2000).]

 

I dont think you would like a 347 it is a good torque monster but you would not get another 200,000 out of it it is not a good street motor. Another thing you might think of is Head work your speed density system can handle that but not a cam shaft switch. With a good set of heads and a fresh motor look out. If you need any more info feel free to email me I will be glad to help Billy

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95 F-150
91 5.0 LX 12.20@123mph
Loves Jesus

 

BillyD- I've decided to just rebuild it and add a vortec supercharger.I'm going to get the superchip for Christmas.You did mention different heads.How do you feel about trick flow heads? A friend of my thinks I should get a pair of the aluminium heads but I told him only if he was buying them. Do they make a pretty good set of castiron ones or should I look elsewhere?(possibly a junkyard for some 351w heads.)

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92flareside 302-5speed
k&nfilter,march underdrive pulleys,flex-a-lite fan,heddman headers w/ true dual exhaust

[This message has been edited by nomad (edited 11-27-1999).]

 

Nomad,

Any news on the project? I'm in the same boat--and would like to know how your mods did.

Thanks,

Mike

 

Pastmaster,
I think one of us is confused here. I think on a 347 stroker, it is not bored any over stock. It is probably just a different crank and pistons. I think that stroking a motor is just that, making a longer stroke. Obviously you would bore it a little to make the cylinders perfectly round.
Using rough measurements, a 3.5 inch bore and a 4 inch stroke which are about a 302, you get 38.465 CI per cylinder. Boring this .050 over, you get 39.572 CI per cylinder. This adds only 9 CI to the engine. You would have to bore it about .25 inch to get that many more cubes. I think this is impossible.
By the math, I think I am right. It may be a combination of the two, but the overbore just doesn't add too many CI.

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Rob
89 F150 4X4
300 I-6, 5 spd
For Off Road Driving

 

I don't know Rob, I got 341.81. Thats 5.19 cid's missing. Roughly 0.649/cylinder. Wouldn't you bore .060 over to get 347? Here's what I got. The 302's stroke is 3.00. I got 346.61, roughly 347. If you bore .30 over you would get 344.21. I know for a 355, there is .360.

To achieve the 355 cubes, it would have to bore each cylinder .360 over. Most small blocks are considered scrap if they need to be bored any more than .060 over. Even if you put a 351 crank and pistons in a 302, (not sure if you can) it would make it 326.5 or 327 if you will.

I would be afraid to invest any amount of money into something like that when I am unsure of the long term durability.You simply can not make a big-block out of a small-block and expect it to last longer than a set of tires.





I know when I helped a buddy build his engine for his 72 chevy pickup, we had a 350 block with a 402 crank. Made it to be 377. We didn't do any boring for it. Its very possible.

[This message has been edited by Pastmaster (edited 03-05-2000).]

[This message has been edited by Pastmaster (edited 03-05-2000).]

[This message has been edited by Pastmaster (edited 03-05-2000).]

[This message has been edited by Pastmaster (edited 03-06-2000).]

 

Mike- had to put the project on the back burner.I'm currently in process to buy a new house.Unless I win the powerball,I can't have my cake and eat it to!There's so much I want to do to the red pig (my truck) I don't know where to start. I'll probably end up with a supercharger. I'm also kicking the idea around to swap cpu's from a 'tang GT with mass air with my speed density cpu. The latest project I'm due to accomplish after house hunting is to put some 3.73's in the rear end hopefully with limited slip.If something does take root enginewise,I'll keep you posted.

Tyler

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92flareside 302-5speed
k&nfilter,march underdrive pulleys,flex-a-lite fan,heddman headers w/series 40 flowmasters, true dual exhaust,jacobs electronics pro-street ign. system,drop-in bed liner,diamond plate truckbox,cobra 29classic CB with 200w linear

 

The 289, 302, 351 and 400 small blocks all have 4.0" bore, stock. The stock strokes are 2.87", 3", 3.5" and 4" respectively.

You can not put a 351 crank in a 302 unless you have some sort of custom pistons at the least. I don't kwow if the main bearing journal diameter is the same. I agree that any more than 0.060" overbore in a small block Ford is pushing it.

[This message has been edited by dirt bike dave (edited 03-05-2000).]

 

The 347 is a "stroked" 302, not bored. It has a larger diameter throw on the crank creating longer piston travel. If it is bored (and I don't have the math with me), it would not be bored more than .030.

Slik

 

Pastmaster,
Your right, boring a ford small block out that much would make it very unreliable and inefficient if it is even possible. I don't think it is. I have never heard of anything over .060. So, it has to be stroked. My math was rough with too much rounding. Thats where the discrepency was.
I didn't know that Ford made a 400 small block? I thought that was only Chevy? I heard something about a 351W with a modified 351M crank to get about 428 CID. Anyone know about this? I happen to have a 351M crank laying around. I would love a 428 CID small block!

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Rob
89 F150 4X4
300 I-6, 5 spd
For Off Road Driving

 

Dave, your right, the stroke on the 302 is 3.00 and the stroke on the 351 is 3.50

If you don't bore the 302 out any for the 347 stroker, how do you get the extra cid's? The 347 uses a 3.40" stroke? I don't have a calculator on me, but I know there are some numbers missing. Thats how I came up with the .60 over in the first place. I don't know about it myself, really.

A 400M is basically a 351M with 4.00" stroke. The bore is the same. Other than that, the two are excatly the same.

[This message has been edited by Pastmaster (edited 03-06-2000).]