347 Stroker

[89FoxVert]

Will a stock block from a 89 hold up to a 347 stroker kit?

 

[347HO]

When the block is cleaned, inspected and deemed acceptable for machining... the answer is "maybe".

Machining and attention to details is crucial, as well as some luck.

Ensuring round cylinders, a square deck, crank and cam bores are in alignment need to be near perfect.

A good to great rotating assembly helps make balancing less expensive. This includes a really good damper if you choose not to go "zero balance".

Ring gap, ring gap, ring gap...
So important!!!
Bearing crush and clearance very important... It has to be right!

So many people blame the 302sbf for failing, when in most cases it was the engine assembler, or choice of cost over precision.

My factory sbf 302 has over 400 hrs capable of putting down well over 600hp, 600 lbs tq on demand.
I run her on the fat side, and oil temp is closely watched.

There are so many issues here that cannot be covered in one "blanket" statement. You will have to find a machinist you trust and start from there.

IMO, now that my race car is complete... It was the journey of the build, the people I met, the pure facts vs heresay all of which I enjoy just as much as driving the car.

 

[89FoxVert]

When the block is cleaned, inspected and deemed acceptable for machining... the answer is "maybe".

Machining and attention to details is crucial, as well as some luck.

Ensuring round cylinders, a square deck, crank and cam bores are in alignment need to be near perfect.

A good to great rotating assembly helps make balancing less expensive. This includes a really good damper if you choose not to go "zero balance".

Ring gap, ring gap, ring gap...
So important!!!
Bearing crush and clearance very important... It has to be right!

So many people blame the 302sbf for failing, when in most cases it was the engine assembler, or choice of cost over precision.

My factory sbf 302 has over 400 hrs capable of putting down well over 600hp, 600 lbs tq on demand.
I run her on the fat side, and oil temp is closely watched.

There are so many issues here that cannot be covered in one "blanket" statement. You will have to find a machinist you trust and start from there.

IMO, now that my race car is complete... It was the journey of the build, the people I met, the pure facts vs heresay all of which I enjoy just as much as driving the car.

Thanks for answering my question. Your opinion really helps.

 

[broncojunkie]

When the block is cleaned, inspected and deemed acceptable for machining... the answer is "maybe".

Machining and attention to details is crucial, as well as some luck.

Ensuring round cylinders, a square deck, crank and cam bores are in alignment need to be near perfect.

A good to great rotating assembly helps make balancing less expensive. This includes a really good damper if you choose not to go "zero balance".

Ring gap, ring gap, ring gap...
So important!!!
Bearing crush and clearance very important... It has to be right!

So many people blame the 302sbf for failing, when in most cases it was the engine assembler, or choice of cost over precision.

My factory sbf 302 has over 400 hrs capable of putting down well over 600hp, 600 lbs tq on demand.
I run her on the fat side, and oil temp is closely watched.

There are so many issues here that cannot be covered in one "blanket" statement. You will have to find a machinist you trust and start from there.

IMO, now that my race car is complete... It was the journey of the build, the people I met, the pure facts vs heresay all of which I enjoy just as much as driving the car.

Username checks out.

 

[Rivsrul]

So I just got done with a 347 build on a stock 302 block in my 1985. My engine builder was not too concerned with the block handling it however the rotating assembly is a much bigger concern. The builder install a new scat crank and it broke after 10 ,
Mins at idle. So needless to say be careful with all aspects of an engine building process

 

[347HO]

So I just got done with a 347 build on a stock 302 block in my 1985. My engine builder was not too concerned with the block handling it however the rotating assembly is a much bigger concern. The builder install a new scat crank and it broke after 10 ,
Mins at idle. So needless to say be careful with all aspects of an engine building process

Interesting...
Was the crank a recent, new purchase, used, or a new but 1st gen crank?
I bought a new, 3.40" scat crank 15 years ago, had it zero balanced, and polished, built the assembled the block complete with carb and sold it to a local enthusiast.
Has been running it ever since, going to shows and races and still no issues.

I was told, but can't confirm with personal experience, newer scat products are crap. I was told runnout measurements, bearing surfaces and throws are shit.

Just curious what your crank looked liked out of the box. I'm talking about physical appearance as well as measurements and balance.

As I mentioned previously... If the machinist, owner, builder didn't do their due diligence to details, more than likely, the driver will be disappointed with performance.

 

[Rivsrul]

Interesting...
Was the crank a recent, new purchase, used, or a new but 1st gen crank?
I bought a new, 3.40" scat crank 15 years ago, had it zero balanced, and polished, built the assembled the block complete with carb and sold it to a local enthusiast.
Has been running it ever since, going to shows and races and still no issues.

I was told, but can't confirm with personal experience, newer scat products are crap. I was told runnout measurements, bearing surfaces and throws are shit.

Just curious what your crank looked liked out of the box. I'm talking about physical appearance as well as measurements and balance.

As I mentioned previously... If the machinist, owner, builder didn't do their due diligence to details, more than likely, the driver will be disappointed with performance.

Well the entire rotating assembly including the crank was brand new. Apparently the scat cranks are manufactured in China and machined here in the states. Now in fair honesty this was in the middle of covid however with a little research on the net I am not the only person that has run into this problem thank god Wayne’s engine rebuilding stood by their work and rebuilt the entire motor now it run’s awesome