How Do I Build a 347 Stroker
The Ford 302/289 engine family has been around since the 1960's. With the desire of today's engine enthusiast's to always make what the factory did better we have come a long ways in the aftermarket world as far as parts and combinations that can be installed into any small block Ford with minimal machine work to the block.
The 347 Ford stroker combination as well as the 331 can be installed into any 289 or 302 factory or aftermarket block. Here at RPM Machine we have tons of combinations depending on your engine needs.
You have choices on bore starting in a 4.000 standard bore and going all the way up to 4.185 bore found in aftermarket blocks from companies like Dart or World Products.
Compression ratio combinations from 8.0:1 for blower or forced induction engine, 9.0:1 -10:1 for pump gas builds and dome pistons for race fuel and alcohol combinations.
Rods from I beam to H beam and cranks from cast steel, steel and even billet steel.
The first thing to consider in building your engine is exactly how much power you want to make and what the rpm's are going to be?
Then ask yourself what your budget is for the build. If you are wanting to make 600+ hp and you have a budget of $2000 it is not going to happen. Be realistic with your expectations and the money you have to spend. If you are building a street machine and only have a budget of $2000 or so plan on building something in the 400 hp range that will hold together and give you some good reliable power without breaking the bank.
Stock long block core $300-$500 with a stock block you will have to do all of your basic machine work to get it ready to go, where with an aftermarket block all you will have to do is final size the cylinders and put the engine together.
You can plan on around $600-$1000 in machine work if using a factory block depending on your local machine shops prices and what actually needs to be done.
Things to look at and or have done would be:
1- Cleaning of the block
2- Bore and hone cylinders with a deck plate
3- Pre-assemble short block and notch bottoms of cylinders for rod clearance, check deck heights, square up the deck of the block so piston heights are the same in all cylinders.
4- Check and or align hone the block
Aftermarket blocks are nice as they are new and the material used to make the block and the machine work done on it at the factory far exceeds that of the OEM Ford blocks.
Dart SHP Block $1850
Dart Sportsman $2299
Dart Iron Eagle $2699
Stock heads, (purchased on your core) $0.00
Machine work on stk heads runs approximately $300-400 for a general rebuild on heads not including parts. This should include cleaning and checking for cracks, 3 angle or better valve job, installation of new guides, surface of the heads and assembly.
Springs to match performance cams depending on lift and type of camshaft $40-$120 new retainers if needed $30+, Valves stk type $80 for a complete set up to $200+ for stainless.
Pocket port on heads to help flow numbers $250+. Total to rebuild and set up a stk set of heads with factory type rocker system runs around $550-$600 with stk valves (new), springs for a hydraulic cam with new retainers and pocket port work.
You have a ton to choose from. You will need to make a decision rather you want cast iron or aluminum? Cast iron is great for all applications,trucks, cars, street performance etc. Cast iron heads are nice as they will have the same growth rates as what your block has. Aluminum grows faster than cast iron causing a scrubbing affect on the head gasket which requires a performance gasket specifically designed for that type of application. Aluminum heads will also require the use of some type of aftermarket head bolt and or stud kit that uses a hardened washer to tighten against so you do not damage your new heads when torquing them down.
The next thing to think about is that with all aftermarket heads you will have to also purchase an aftermarket valve train systems as they use a guide plate and stud type mounting system and an adjustable rocker arm. The heads if purchased assembled will come with the studs and guide plates but you will have to purchase new hardened push rods to run with the guide plates and a new set or rocker arms. Push rods can run from $35-$100 and rockers can run from $109-$400 depending on make and material used.
Cast iron heads from Dart or World Products if purchased already assembled will start at about $599 per head. There are some off shore heads out there that are cheaper but be careful with what you are purchasing as you usually get what you pay for!
Alum. heads will start off at around $750 per head and once again there are cheaper heads out there just be careful. The last thing you want to do is save $200 or so dollars on a set of heads and have it end up blowing up all the rest the parts you have purchased ultimately costing several thousand extra to fix. You also need to be careful in picking out your heads to make sure that the intake runner size is proportional to the size of your engine. Don't purchase a 235 cc intake runner AFR head and expect a 347 cubic inch street car to be able to utilize that large of a head. The smaller cubic inch Ford engines just can not get that much intake volume moving and you end up hurting your over all power output in the long run. Match intake size to cubic inches and rpm turned.
347 Stroker Kit:
Once again you have to be careful with what you purchase as you get what you pay for. There are kits being offered on the internet these days on Ebay and on some sites starting out around $500. These kits are put together with the cheapest price possible in mind not quality. A good starter kit for a truck will start off around $650 and go up from there. RPM builds our kits starting off with 4340 steel rods not the cheaper 5140 rods and we always use the aftermarket cap screw design connecting rod bolt design instead of the factory type bolt and nut set up. We can substitute the cheaper rods into your kit for you but you are usually only saving $100 or so and ending up with an inferior product.
From the $650 price you will add bearings and rings $120 and then balancing $185.00. We offer new damper and flex plates in a 28 oz set up for $111 for the combination. This brings the cost of a rotating assembly to 650+120+185+111=$1066. Once again we have cheaper kits and we have more expensive kits it all depends on what your budget and expectations.
Total cost at this point to build a 347 stroker on a respectable budget (not trying to do it as cheap as possible):
Block work- $1000 with the cost of a core.
Head work on stk heads $300.00
All new stk parts in heads $120 (springs up to .500 lift stk valves)
Stroker kit balanced w/damper and flex plate $1066
Ball park on the rest of the parts hydraulic cam $300 or so