Are the heads interchangeable? I currently have a 302 with gt40p heads they have a ton of work done to them. I might be going to a 351 will they just bolt on? Thanks
yes and no. the head gaskets are basically the same, there might be a steam hole that needs to be drilled in the head or block depending on the year block you are using. the 351w used 1/2" head bolts, where as the 302 used 7/16" head bolts. so using 302 heads on a 351w means a tighter clearance between teh bolts and the head bolt openings, not really an issue unless you are using head studs. you also need to use a different 351w intake. remember that the early intakes on the 351w used an L shaped coolant passage in the head, as well as two extra bolt holes for the intake on each side. later ones, i think after 1974 or so, changes over to the 302 style intake with a more normal coolant passage and six bolt holes per side. also note that 351w heads generally have large combustion chambers to keep the compression ratio down to about 9.5:1, and using the 302 heads with their smaller chambers can push the compression ratio up about 1.5 points, so be aware of that also. do some serious calc time on a compression ratio calculator and be sure of where you are going to be compression ratio wise before running the combination.
Earlier year 302 engines where externally balanced with a 28 oz balancer. Newer year 302 engines where externally balanced with a 50 oz balancer. Is there a benefit to the heavier balancer, or the lighter balancer?
there is no real benefit with either balance system. ford made the change to improve fuel economy numbers with their bread and butter engine. the 50oz balance rotating assembly is a bit lighter, which means there is less mass to spin up to speed, which means less fuel to accelerate the engine to speed, etc.
in the end however for the street you will never feel the difference either in acceleration or in fuel economy numbers. however, in my opinion for the street you are better off with the 28oz balance factor as the cranks have the extra counterweights back and are thus less likely to have to deal with torsional flexing.
My budget is currently one piece at a time as I can afford it. Not the best plan, I know, but it's what I have. And currently, I have an existing crank and rods that should work, since they are currently working in the car. I'm also thinking I want to keep my current block to keep matching numbers, so not sure if stroking is the best idea. There is always a risk buying a stroker kit sight unseen from an individual that doesn't live anywhere near me. But $400 to $450 sounds like a great price! What is a reasonable price to get the block clearanced for a 331 or 347?
you may not have to clearance the block. it depends on what rods you use as to whether you need to clearance the block or not. the only way to find out is to do a mock up assembly. and you dont need to buy a whole kit all at once, you can buy the parts piecemeal if you wish. the crank for instance can be sourced from here;
this is but one example of the cranks that summit racing has. add to that the connecting rods and pistons later on as you can afford them. this way you get new parts instead of wondering if the parts you bought used are any good. once you have the rotating assembly, you want to mock assemble the bottom end, IE install the bearings, crank, and a rod and piston combo, you only need one, but you can do all eight if you wish, but it is more work. you will take that one rod and piston and install it in each cylinder, no rings to make it easy to get in and out. and the rotate the crank through at least one complete revolution by hand and note each place where the rod bolt either just clears or just touches the cylinder wall skirts. if you have at least .060" clearance, you dont need to do anything, less than that though and you need to take a die grinder and create the needed clearance. be sure to wash the block thoroughly when you are done.
Stroker kits are easy to come by on the Mustang forums from guys who have run out of cash, divorce, or some other event. I got my 331 kit (crank, pistons, rods, rings, and bearings) for $450 and I missed one for $400 the day before.
Darren
yep, just need to shop around and be willing to make deals. i will say however that if you do buy parts from someone who "never used them" check the parts over very carefully, and deal accordingly.
I had a 1984 Continental hardtop with the 5.0 CFI motor. All electronic with lots of bell and whistles! That car was very comfortable but started having problems with air ride and the steering rack lost power assist to one side of the rack. I got it with 194k miles and it ran great for a CFI motor, I unloaded it with around 210K miles.
These were availble till 1987, only came with either a 4cylinder diesel and the 5.0 V8 in either CFI or SEFI; only Standard Output motors (302 firing order). I would love to have another one, with low miles and preferabbly the SEFI motor and convert to HO.
ABS pumps and air ride can be very expensive to fix for these cars along with the digital dash and trip computer/automatic temperature control. One cool feature is the 1/4 windows in the front doors are power and roll down before the big window goes down if I recall. They definitely have that fox chassis feel to them.
wrong, the BMW diesel engine used on the mark Vll was a 2.4 liter SIX cylinder engine
Thank you for the input. I'm not sure the 331 would be in the budget, but more torque would be nice.
well, lets look at that shall we? what is your engine build budget here? perhaps we can figure a way to get you to a stroke motor.
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I'm definitely planning on changing the firing order to the HO order. I've heard it is easier on the bearings, and that's what the maf mustang computers run.
that was the theory behind ford changing over when they brought out the 351w. the idea was to reduce the load on the front main bearing as the 289/302 had issues with spun front main bearings(ask me how i know ). the problem though is that it put extra load on the second main bearing, and 351ws had issues with spun second main bearings(again ask me how i know:evilgrin:). so change the firing order if you wish with a cam swap, but dont do it because it "Saves" the bearings, it doesnt. proper engine assembly procedures save bearings.
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I've heard that someone that knows what they are doing would benefit from a MegaSquirt setup, but I'm much more plug-n-play. lol
actually the megasquirt is fairly easy to tune for the amature. check out the link i posted for information, including install articles, and as i recall an actual forum to discuss megasquirt issues. but you might be surprised at how easy todays megasquirt systems are to tune. yes in the old days the original magesquirt system was like the early apple computer days, you bought a bag of parts and some instructions, and then sourced other parts from a list, and you assembled your own system, including building the box everything went in. and then you had to program it. then diyautotune stepped in, took the megasquirt ball and ran for the end zone. they started off just building ECUs so you didnt have to. all you had to do was build teh wiring harness and lay on the tune. today however, diyautotune now has wiring harnesses, sensors, comm cables, initial tunes, in fact they have pretty much all the fun little bits you need to make the system work.
i highly recommend that you check them out, even if you dont use their stuff, you will find all kinds of interesting information there.
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Ya, looking at the room around the engine, I went ahead and got some unequal length shorty headers to save the headache of trying to clear the tight spots on the driver side.
I always thought they fell under the Personal Luxury classification but a friend of mine, who does love Fords, says no. EPA calls it a compact.
the EPA be ed, these cars are personal luxury cars, or so says ford since 1958 when the first four seat thunderbird were rolled out to a public hungry for such cars. and they have usually been considered a midsized car based on external dimensions at the time of production.
That 255 is a weird motor, I cooked mine due to loss of internal oil pressure with no sign whatsoever. That was 20 years ago, but it was quite the weezy motor from the get go. I bet everything Ford put into that motor was oddball, I wonder what they had parts left over from to use for the 2 years they ran the 255?
it wasnt that oddball of a motor. the heads were severely restricted, as was the intake and exhaust, but that could be cured by bolting on the heads, intake, and exhaust from a stock 302. the bore on those motors was 3.68" with a 3" stroke, and us inline six guys use those pistons in the old 250 to bump the compression up where it should be. also a cam swap does wonders for the little 255, and so do gears.
the NHRA had some serious reverence for the 351c also. in fact they had so much reverence that they had some of the toughest weight breaks on cars powered with the 351c. bob glidden built 340ci cleveland motors tended to dominate pro stock racing, so much so that in 1978 glidden won both the NHRA and IHRA rpo stock titles with a PERFECT winning record, it was 32-0 that year. and to prove it wasnt just the motor, he switched to hemi power in a plymouth arrow in 1979 and won the championship again in NHRA. after that the small blocks were retired and the NHRA and IHRA went to 500ci and unlimited mountain motors respectively, and glidden STILL dominated.
and trust me, you havent lives until you have felt a 707ci normally aspirated motor lay down a mid 6 second run while you are stnding at the 1000ft mark. its almost and intense as a top fuel dragster at full song at the same mark.
My 5.0 has a lot of miles on it and is getting tired. :( I don't race it, but like to have something with more torque than stock.
I have an almost stock 5.0 in my 1987 Thunderbird Sport. It has a Professional Products intake and throttle body, I think it's 75mm. Other than that and a better coil, distributer module, and alternator, it's stock. Based on my reading on here and other places, I'm thinking of the following build, and would like to get some opinions.
I want to keep the numbers matching, so am having the stock block refreshed. New pistons, bearings, gaskets. I want to use AFR 185 heads, so the need for the new pistons to clear the 2.02 intake valves. I'm thinking of using a Comp Cams Xtreme Energy 258/266. Duration 258/266, lift .533/.544, lobe separation 112. The firing order is currently the non-HO with Speed Density computer, so will have to change to MAF computer with HO firing order. I'm thinking a MSD 6AL would be good insurance to make sure I don't run the engine over 6000 rpm so it will last longer. I'm planning on re-using the existing intake, distributor, and as much as I can.
Questions:
1 Anybody running this setup? 2 What size injectors would you suggest for this setup? 3 Would the hassle of trying to get long tube headers to fit be worth the difference in power from shorty headers? 4 What important question(s) am I not asking?
ok a few things;
1: with the cam you want to run, i suggest stroking the engine out to a 331ci motor. the extra stroke and the cam you selected will give you a fairly monster torque curve. the nice thing about getting a stroker kit is that you can order up the pistons from the kit manufacturer any way you want. tell them you want flat top pistons with valve reliefs for the valves and the cam in question
2: the AFR185 heads are just fine for the combination
3: when you select the cam, make sure you get the firing order you want, it has to match the computer for best results
4: instead of locating a factory computer, i suggest going with a megasquirt computer. that way you can tune it to suit your engine, and you can have an ignition controller built in if you wish. check out this site for more information http://www.diyautotune.com/
5: since you are just building a street motor, i wouldnt bother with getting long tube headers, or even equal length shorties. i would pick up a nice set of 1 5/8 tube shorty headers as inexpensively as possible.
6: i believe a 24lb injector will fit the bill nicely in this motor
the 3.8 heads are all the same right up until they changed over to the split port head. then all the split port heads are the same, 3.8 or 4.2. and it doesnt matter if the heads come off am FWD or RWD car, you can use any of them.
now on to a bit of advice for you, if you want to end head gasket problems, grab a 4.2l motor from a 2002 or later F150. these are split port heads, and the engines are rated stock at over 200hp. to make the swap you will need to go one of two directions;
1: grab the wiring harness and all the sensors along with the engine, and swap the whole mess into your current ride
2: change over to a carb set up with the split port heads.
check out tom morana racing or supersix motorsports for the necessary parts.
one more thing, if you want to keep your stock block, you can swap over to the split port heads without issue as the heads will bolt up. and by the way you want to use either the good felpro blue head gaskets or the better corteco mls head gaskets. i also suggest replacing the head bolts with ARP bolts as well, though studs would be better.
The 255 cranks is no more than 5 to 6 pounds lighter.
Using a 255 crank in a 600 horse engine is laughable at best. With any kind of power adder, it won't last long. We all know that stock blocks are none too long-lived anyway. Put a belt drive supercharger on there and it's even less.
Buy a good forged crank, and have it worked by a reputable shop. Nobody gets far with junkyard stuff.
well, that depends. if you are buying a 351c crank from a junkyard, and it is in good shape, it WILL handle better than 600hp despite being a cast crank.
Quote from: Haystack;424383
the 255 crank will outlast a stock block. most aftermarket cranks are cast, and most factory ones are.forged.
yeah sorry, but you corrected yourself after being admonished.:D
to the OP, dont even bother with trying to use the 255 exhaust manifolds on anything, even another 255. the stock 302 exhaust ports are small enough, but ford made the 255 head ports even smaller, with the manifolds to match. they are restrictive as heck, and even ported they flow like .
). the problem though is that it put extra load on the second main bearing, and 351ws had issues with spun second main bearings(again ask me how i know:evilgrin:). so change the firing order if you wish with a cam swap, but dont do it because it "Saves" the bearings, it doesnt. proper engine assembly procedures save bearings.