302 to 347
Thread Starter
5th Gear Member
Joined: Jun 2005
Posts: 2,258
From: So. California
302 to 347
hey guys been gone a while. got married and the mustang has been in the body shop for about 6 months. The friend doind the body work has been in the hospital with his father so its been on hold for a while.
anyhow i was going to take the stang up to a friends shop to do a cam swap so i can put my afr heads on. I have a roller block 302 and i have afr 185's, airgap, new rockers, and holley SA 750 sitting in the garage. this friend of mine is going to teach me to do the cam swap so i was thinking why not stroke the motor while we are at it? My question is how the hell do i know what kit to buy? are there different length/size rods and pistons? block clearance issues? heads might need to be notched? How does it all get balanced? Is SCAT a good way to go? Forged?
anyhow i was going to take the stang up to a friends shop to do a cam swap so i can put my afr heads on. I have a roller block 302 and i have afr 185's, airgap, new rockers, and holley SA 750 sitting in the garage. this friend of mine is going to teach me to do the cam swap so i was thinking why not stroke the motor while we are at it? My question is how the hell do i know what kit to buy? are there different length/size rods and pistons? block clearance issues? heads might need to be notched? How does it all get balanced? Is SCAT a good way to go? Forged?
3rd Gear Member
Joined: Apr 2008
Posts: 593
From:
RE: 302 to 347
That's a lot of questions....
Your roller block will have to have the bottoms of the cylinder walls notched to clear the longer stroking rod. There's a tool on eBay for around $25 to help you make the cut in the correct spot.
With your 185's, the pistons will have to either come flycut or be flycut to not intefere with your oversize (2.02?) intake valves. The heads don't get notched, the piston tops do.
SCAT forged components are the way to go, that's what I'm running. You can either buy an a balanced kit or have it balanced locally. The usual rod length on a 347 is 5.40". This places the rod high in the piston and usually intersects the oil control ring on the piston skirt. You can buy rods with a 5.35" length that just barely leave the oil control intact (I recommend this).
If you're looking for impressive power, IMO the stroker motor is the way to get there. Even a 331 is a great improvement over the 5.0
Good Luck!
Dave
Your roller block will have to have the bottoms of the cylinder walls notched to clear the longer stroking rod. There's a tool on eBay for around $25 to help you make the cut in the correct spot.
With your 185's, the pistons will have to either come flycut or be flycut to not intefere with your oversize (2.02?) intake valves. The heads don't get notched, the piston tops do.
SCAT forged components are the way to go, that's what I'm running. You can either buy an a balanced kit or have it balanced locally. The usual rod length on a 347 is 5.40". This places the rod high in the piston and usually intersects the oil control ring on the piston skirt. You can buy rods with a 5.35" length that just barely leave the oil control intact (I recommend this).
If you're looking for impressive power, IMO the stroker motor is the way to get there. Even a 331 is a great improvement over the 5.0
Good Luck!
Dave
Thread Starter
5th Gear Member
Joined: Jun 2005
Posts: 2,258
From: So. California
RE: 302 to 347
So find a forged SCAT kit that is already balanced and flycut? intake valves are 2.020 they are part #1422 from AFR. How bout what cam? Is this a pretty easy build? Im undecided on a carb as well. was going to find a dyno tune place and let them pick a carb that they like to work with.
3rd Gear Member
Joined: Apr 2008
Posts: 593
From:
RE: 302 to 347
How bout what cam? Is this a pretty easy build?
The 347 bolts together just as easily as the 5.0... pretty simple stuff really.
Dave
3rd Gear Member
Joined: Mar 2006
Posts: 971
From: Apison, TN
RE: 302 to 347
Ok, I also have experience with these engines, and have built 2 of them. One of which is my own and is in my car. First of all, buy a complete kit. SCAT or Eagle are both great quality (I run Eagle). As far as a forged crank, you don't need it if you are running a stock block. This is simply because the cast cranks scat and eagle offer are stronger than the block. You will split a stock 302 block right down the middle before the crank breaks. Most kits do come with Forged rods, and I reccommend those. For pistons, Hyperuetectics will be just fine. They are lighter than forged pistons and will allow the engine tospin up faster. They will also handle up to a 200 shot of spray, but there again, that would more than likely split the block, so forged pistons are not neccesary. No matter which kit you buy, the pistons should alreadyhave large enough notches to clear the valves in the heads. My eagle kit came with Flat top (with large valve reliefs)hyperuetectic Speed pro pistons that have the skirt coating. They also have a special oil ring that helps prevent oil burning. I like the longer rod (5.4) because there is a better balance on the rod ratio, and I have no complaints about my setup (doesnt burn any oil at all). As far as the cam, definately run a roller. Call comp and see what they reccomend, they have a much larger selection than Edelbrock. And finally, your carb. 750 is going to be too big. It is way better to slightly under carb an engine than to over carb it. I would reccomend a 650 for it because the streetability will be a lot better with it over the 750, and the only time the 750 would make a difference would be at 7000+ RPM, which you more than likely wont be turning. At RPMs lower than that it will hurt you. Just my 2 cents worth, and this is definately a situation where I can say, "been there, done that," just like a few other folks on here. 
4th Gear Member
Joined: Oct 2006
Posts: 1,443
From: Canada
RE: 302 to 347
Those stroker kits are good entry level kits, just don't cheep out on all the internals. Don't worry about "splitting" a block,you will never get the HP numbers to do that without spending way more on the heads and power adders. I would recommend sending the block out to get decked and line honed so you have a good square block to start with. This will cost a couple of dollars but will save you headaches in the long run.
And remember, you get what you pay for. Good Luck...
And remember, you get what you pay for. Good Luck...
5th Gear Member
Joined: Jul 2007
Posts: 2,553
From: Detroit; where the weak are killed and eaten.
RE: 302 to 347
ORIGINAL: tyler72
Ok, I also have experience with these engines, and have built 2 of them. One of which is my own and is in my car. First of all, buy a complete kit. SCAT or Eagle are both great quality (I run Eagle). As far as a forged crank, you don't need it if you are running a stock block. This is simply because the cast cranks scat and eagle offer are stronger than the block. You will split a stock 302 block right down the middle before the crank breaks. Most kits do come with Forged rods, and I reccommend those. For pistons, Hyperuetectics will be just fine. They are lighter than forged pistons and will allow the engine tospin up faster. They will also handle up to a 200 shot of spray, but there again, that would more than likely split the block, so forged pistons are not neccesary. No matter which kit you buy, the pistons should alreadyhave large enough notches to clear the valves in the heads. My eagle kit came with Flat top (with large valve reliefs)hyperuetectic Speed pro pistons that have the skirt coating. They also have a special oil ring that helps prevent oil burning. I like the longer rod (5.4) because there is a better balance on the rod ratio, and I have no complaints about my setup (doesnt burn any oil at all). As far as the cam, definately run a roller. Call comp and see what they reccomend, they have a much larger selection than Edelbrock. And finally, your carb. 750 is going to be too big. It is way better to slightly under carb an engine than to over carb it. I would reccomend a 650 for it because the streetability will be a lot better with it over the 750, and the only time the 750 would make a difference would be at 7000+ RPM, which you more than likely wont be turning. At RPMs lower than that it will hurt you. Just my 2 cents worth, and this is definately a situation where I can say, "been there, done that," just like a few other folks on here.
Ok, I also have experience with these engines, and have built 2 of them. One of which is my own and is in my car. First of all, buy a complete kit. SCAT or Eagle are both great quality (I run Eagle). As far as a forged crank, you don't need it if you are running a stock block. This is simply because the cast cranks scat and eagle offer are stronger than the block. You will split a stock 302 block right down the middle before the crank breaks. Most kits do come with Forged rods, and I reccommend those. For pistons, Hyperuetectics will be just fine. They are lighter than forged pistons and will allow the engine tospin up faster. They will also handle up to a 200 shot of spray, but there again, that would more than likely split the block, so forged pistons are not neccesary. No matter which kit you buy, the pistons should alreadyhave large enough notches to clear the valves in the heads. My eagle kit came with Flat top (with large valve reliefs)hyperuetectic Speed pro pistons that have the skirt coating. They also have a special oil ring that helps prevent oil burning. I like the longer rod (5.4) because there is a better balance on the rod ratio, and I have no complaints about my setup (doesnt burn any oil at all). As far as the cam, definately run a roller. Call comp and see what they reccomend, they have a much larger selection than Edelbrock. And finally, your carb. 750 is going to be too big. It is way better to slightly under carb an engine than to over carb it. I would reccomend a 650 for it because the streetability will be a lot better with it over the 750, and the only time the 750 would make a difference would be at 7000+ RPM, which you more than likely wont be turning. At RPMs lower than that it will hurt you. Just my 2 cents worth, and this is definately a situation where I can say, "been there, done that," just like a few other folks on here.
And along with LCC, you really do get what you paid for. Spend a couple extra bucks now, and it'll save you tremendously in the long run.