Engine Is DOA- New build- measuring for zero deck?

a91what

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Apr 6, 2011
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#1
If you follow my build thread you know that my engine recently failed a compression and leakdown test, basically the rings are toast. I am looking for advice on what bottom end to build for the new engine. I can list what parts i am going to be reusing from the current build and was hoping some of you guys that have more experience can chime in.

-Ported GT40 3bar heads with 2.02 1.6 valves drilled for 7/16 stud mount rockers
-My custom M112 Blower setup
-Front engine dress


I am on the fence about what i should do for a short block, The current block is a xxx casting but has been machined twice and is 30 over now. I was contemplating buying a new block to build, possibly using an explorer long block to start over with.
Now comes the goods should i use the explorer crank and rods and get forged pistons to build a 302, this would allow me to use my current flywheel and balancer and keep cost down. OR should i pony up for a 347 stroker kit and feed it the 10 psi my current 306 is seeing?

I would like advice on a cam but think i may go custom to pull the whole thing together.
 
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hoopty5.0

mechanicus terribilis
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#2
depends on what you wanna spend... You can get an explorer motor for cheap, or spend a ton on a stroker. If it were me, I'd but a cheap shortblock to get it running again and then start saving for a better motor while you still get to drive it.
 

a91what

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#3
Nah next motor that goes in it i want to be able to handle the boost and timing i throw at it.... i dont like wondering when the piston is going to give up.... That said i think both will make the power that i want, i dont want to rev the engine to the moon, maybe a 6-6500 limit peak power around 5500 would be fine with me. I dont want to go bankrupt building the new shortblock. I just want to reliably make power im not here to win races it is a street car and i have a budget to keep in mind.. but i dont want to cheap out on the important stuff..

I guess what im getting at is if I dont need a forged crank why pay for one? I dont need a shortblock that will out survive the block but it does need to jive well with boost and water meth.
 

hoopty5.0

mechanicus terribilis
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#4
Theres abandoned projects all over the interwebz. I just saw a disassembled 347 for sale.
 

90sickfox

I didn't really have an issue with the stink...
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Mar 2, 2015
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#5
Steve, build a 393...or a 363. It'll handle the power and you can grow with it.

Wish i would've gone that route.

You need an oil pan from a police crown victoria 5.8. The e cam should mellow pout with note displacement. You've seen this swap a few times I'm sure.

Therm again... you'd have to build a new intake, brackets, who knows what else....

I haste to say it.... but.... you may be in Dart block territory now. Atleast, that way you could play with boost.
 

a91what

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#6
My boost level is pretty much stuck where it is now, the blower made 11psi on a 306 cid engine, with a 347cid engine it should make 15% less boost but the same power potential. [rough math]...
I cannot fit a smaller pulley on the blower, i do plan to port the blower but that is more for efficiency reasons.
 

RaggedGT

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#7
Not a lot of experience in this area-so another question rather than a answer/help.
Why not start with a 351?
 

a91what

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#8
For simplicity reasons [also my intake is a custom unit] i want to stick with a 8.2" deck engine. 302 based engine

The main concern is if it will be cost productive to build a 347 vs a forged piston 302 with the 10psi i will be making.

I will be swapping the cam, there is no way that my new engine will be getting a letter cam. I will either run a blower grind cam or have @EDC make me a cam for this setup. I mean how many SBF are running around with an eaton between the valvecovers???
 

stanglx2002

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Jul 7, 2005
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#9
Are you wanting to be above block breaking territory or not is the question?

I was in the same place as you years ago and decided that under 500 rwhp is plenty for me, so just stick with a normal/easy 302/306 setup with that blower setup. You will be more than happy with it in my opinion.
 

Noobz347

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#10
I don't see any reason to spend money on a stroker kit for that blower setup that you have.

Use a stock forged crank. Put new pistons in it. Get the block sleeved if necessary or find another seasoned block. Put HUGE oversized bearings in the whole damned thing and make it bullet proof.

Use rings and pistons that don't give a damn about boost. A one-off blower cam might really wake that thing up. Whatever compression you were thinking about going with, go 2 to 3 points higher. The overall combo will be more responsive.

@EDC

Hopefully he'll pop his head in here and give his two cents after he's seen your thread about the time machine. :O_o:
 

Steel1

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Aug 18, 2017
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#11
My thoughts are also to do a 351w based build. Reason being if you do a stock block
302 based build, stroker or not, and add that kind of boost to it you'll be pushing the limits
of the block.
351w could safely handle that power, imo the swap is not that difficult and can be done
on a reasonable budget.
Of coarse if you go with some form of aftermarket block than it's a mute point.
 

Noobz347

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#12
The problem I see right away with a 351 is about having to re-accomplish all the fancy plumbing and stuff.


However, a 9.5 inch deck will get you a little closer to:

 

a91what

I plan to eventually problem is time
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#13
Hmm... some of you make good points, however I do not need block splitting power. Sure the combo will probably be able to do that, the smaller Eaton made 400ftlbs at the tire, this one makes more boost and carries it all the way to redline... that 400ftlbs was made on this same shortblock with the same bad rings and hyper pistons.

I can always use a larger blower pulley and make less boost. Believe it or not that IS an option.

Let's talk stock block levels for a moment, I like where @Noobz347 was headed, stock crank stock rods? Forged pistons.... I need details on the bearings... not sure what you meant there.
This will keep cost down I can spend my money on other things like a new fuel rail and a decent catch can setup. Maybe even put ac on the car....

Imho 400/400 would make me smile... alot
 

95BlueStallion

Yo Adrian, I did it.
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#15
I have a fully forged 347 (in a stock block) that you would just need to swap cams with... I am seriously considering going back to stock.
 

tannerc91gt

This last 25% is foreign territory at this point
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#16
Don’t say it...don’t say it....don’t say it...
 

a91what

I plan to eventually problem is time
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#20
Hmm... looks like the stock crank is cast but good to 600hp or 7k rpm, stock rods are forged as are 87-92 pistons.

I had no idea the stock bottom end was so stout.
 

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