Sippix

302 to 331 is what I'm talking about.

I've seen about a dozen 302 stroker kits online, and I've decided to go this route rather than buying a larger engine. I've done some preliminary reading on the pros and cons of stroking a 302 to 331. Going 347 seems to be great for power but low on longevity. That's why I'm sticking firm to a 331. Basically, to do all of this, I need to do a complete engine build. I /need/ my current as a DD, so I'm forced to go with a ground-up build.

My goal is to build a 331 with 57mm twin turbos. I really don't want to buy a stroker "kit." Kits give me gas. What I really need to know is, will a stroked/bored 302 gain a lot from the quicker spools of a smaller 57mm turbo? Will the 57mm's force enough air into each chamber at high RPM's?

I understand the concept of stroke dwell times, and it worries me slightly. Will the increased dwell time allow for "too" much intake on a forced induction system and detonate without very high octan fuel? Also, can I offset this factor with a specific/custom cam? Should I be looking at a high rod ratio to prevent a rough low RPM ride?

I'm not sure of the dimensions of the stock crank travel, piston length, rod length, or bore length to do any real mathematics. Knowing these basics will allow me to do the mathematics necessary to select the appropriate size turbos. I think once I can get these factors down, I can select an appropriate cam.

Am I headed in the right direction, folks? What else do I need to factor in? And does anyone know of a book or online article that really gets down to the grit? I love numbers, thermodynamics and and volumetric based mathematics, so I need to read something more than just a generic step-by-step how-to.

Thanks for reading, and thanks in advance for the replies!

BlessedHellride

I wouldn't waste my time with a turbo build on a stock block, much less a twin turbo set up. If I read your post wrong, you stated kits give you gas. I translated that into my little mind that you don't like kits. I can't for the life of me figure that out. I know there are some very high end manufacturers out there that make specific items that may be better quality than what is found in most kits. But there are a butt load of kits that are plenty strong enough for what you are wanting to do. And the kits have everything you need for a basic rotating assembly.

Joel5.0

You are starting your project based on defective information. Just a thought.

Sippix

Oh, I, in no way shape or form, plan on keeping the engine stock with just a stroker kit and a twin turbo setup thrown on there. That's why my need to build a block from the ground up. I want to start with the bottom end, because everything else will be matched to compliment the increase in displacement to increase the potential horse power.

I mean, I'm not looking for an 8 second daily driver, here. But it would be nice to put down at least 500 HP. That's my power goal. I could throw numbers out there all day long, but until I get a firm foundation of parts and function, I don't know what the engine will theoretically achieve.

As for the kits ordeal, I'm not saying they're bad. Most of the high-end manufacturers of those quality components have bundled them into kits. Me, I enjoy the feeling of accomplishement when I look into an engine bay and I can say, "I hand-picked those parts. That's /my/ build."

Sippix

Then, please, by all means do correct me. (That's not sarcasm, by the way.)

I'm new to this, and I won't hide it. Hense the reason I made this post. If I say something and it's stupid or incorrect, then set me straight, folks!

I want to build an engine. No...I -need- to build an engine. I'm not looking for track glory or roasting rice burners. I'm looking for something I can learn, work with, build and make it my own. I'm in it for the long haul, here. I want my Mustang to be a reflection of the dedication and knowledge that I've put into it.

BlessedHellride

If your are not looking more than 500-600 rwhp, go with one of Fords Boss blocks. It will handle all of your power range plus a little more. As far as your statement about 347cid engines not lasting very long. That is very old bull crap information someone has told you. Times have changed, there are alot of guys who have tons and tons of miles on their 347 engines and there are some who cant seem to get a couple thousand out of them. Its all in the parts used during the build and how its built.

I don't think you understand the "stock" block as I stated it before. If you are going to do a Twin Turbo build, you won't make it very far on a "stock" block. With the power output you are wanting and or looking at, the factory block isn't going to stay together very long. Hence my above post and twice in this post, it will be in your best interest to get an aftermarket block to start with and build from there.

BlessedHellride

Not to mention the cost of building a twin turbo car correctly. Holy Crack Rocks Robin!!!
Talk about some dough Ray Me. But if ya got it flaunt it.
I figure a TT kit, with supporting fuel mods, intercooler and whatever is needed for the cars ECM-- probably looking into the neighborhood of 5-6k

An aftermarket block to handle such power?- Cheapest one will be $1600
Machine work required for the new block- Minimum $500
Rotating assembly, beings as you don't want to purchase it as a kit- $2000
Balancing the same pieced together rotating assembly- $200-$400
Transmission to hold such power- minimum $1500(C4), if 5 speed- about $2k-$2500
A rear end to handle such power? Hmmmm? Guess what, another $1000 bucks easy.
Not to mention the cooling system. Probably another $500 or more.

So there you are, looking at $12K, and still not finished. Still have to do the cars suspension. That's and easy $2000 for the front and rear suspension.

Now we are at $14K, what to do, the car still won't run. All the Knick-Knack stuff that is always overlooked- Another $500-$1000.


I'm not trying to defer you away from your project, just want you to be aware of what you are getting yourself into. I know it's not the same, but it would be cheaper for someone to save a little money and purchase a car already finished rather than build it yourself. Trust me, I just finished my last car a couple of months ago and could of purchased a finished turbo car for half of what I got into my Naturally Aspirated Coupe. It's just a thought my man.

Sippix

Oh, oh, oh...Yes, I totally agree with you on that statement. We're on the same page now. In fact, we're on the exact same page. I actually did price a Boss 302 Block, because it certainly is in the power and price range I'm looking for.

As far as the 347 goes, that does make a lot of sense. I'm sure most of what everyone tells me (everyone being much older men whom stopped hot rodding in the 70's) is far out-dated and incorrect at this point-in-time, but I think it's worth bringing up and being corrected on rather than just blowing with the wind.

On another note, I know you mentioned the Boss Block from the top of your head, which means you're already more knowledgable than I am. So, here's my question to you. WI need to grind any material from the block for crank clearance? Or is that all dependant on the crank/pushrod setup I go with?

Sippix

Oh, believe me...I know this will take a lot of dough. I could most likely buy a new model year car for the cash I'll drop on the motor and drivetrain alone. But, it's not like I have a set date for any of this to be done. I'll order the parts piece by piece, month by month and assemble them.

That's not even the deal, though. I'm 26, and I'm getting married soon - Hopefully a child to follow. I want a car that will provide me with all the excitement of a real performance car while being something I can maintain for years to come. Hell, I'd love to be able to keep her long enough to hand over the keys to my spawn. My old man gave me the keys to his ol' Cougar, and even though it was a heap, it still was pretty much the greatest day of my life up to that point.

Heritage, my friend, heritage.

Joel5.0

Interference between the rod and the bottom cylinder skirt.



Boss 302 blocks have shorter cylinder skirts that do not require notching, but need to be checked anyway.