Newbie here,Are the factory SO 5.0 flattop pistons forged or cast?
Cast..... Welcome
Welcome , what he said ^^^^^^
Also, factory SO pistons are NOT flat-tops...they have a considerable dish.
Thanks guys,i've come across a complete 88 T-bird 5.0 from a wreck with 28k miles for $250. It runs great,i just didn't know about the pistons and how much abuse they could handle. What's the compression with that dish with E7 heads? I've got a bunch of old stock mustang engine parts,STD HO pistons,cams,etc collecting dust and was just wantng to know what was the same or diffrent.Thanks for all the info again,Great site! keep it up!
With that little mileage, I'd say leave the SO pistons in it for now. With the E6's compression was around 8.7-8.8:1 but the E7's have a little smaller chamber. Figure around 8.9-9.0:1 with E7's....unless you send them to the machine shop and take .030" off. Then you should be close to 9.3-9.5:1 depending on head gasket.
If you're going to run anything more than an HO cam, the SO pistons will NOT work...not sure about some of the alphabet cams, but the HO cam will work with SO pistons.
Also, as an option, you can have them fly-cut, but for the trouble and cost, HO pistons would be better, plus you already have 'em...
The dish is 2.5 cc.
Depending on what heads are being utilized; this may not be true.
You'll never know 100% for sure unless you measure PTV clearance.
Example: Trick Flows TW heads, flat tops, no valve reliefs, .565" lift and roughly 225 degrees duration @ .050" lift.... LOTS of clearance.....
Depending on what heads are being utilized; this may not be true.
You'll never know 100% for sure unless you measure PTV clearance.
Example: Trick Flows TW heads, flat tops, no valve reliefs, .565" lift and roughly 225 degrees duration @ .050" lift.... LOTS of clearance.....
You should go to the CoolCats.net and read about the H.O. conversion it will probably answer a lot of your questions.
Right, I forgot to put that in my other post...better to err on the side of caution any which way. :D
i'm running a B303 cam with stock flattops and stock e6 heads so thats another one that clears...
The factory E6 heads have their valves recessed much further into the head than E7's or other factory Ford heads.
A local machinist told me he prefers the e6 turbo swirl design chambers to the e7's. He basically said the e7's are junk and everyone gets too caught up with flow numbers of cylinder heads in general. If you know what to do, the e6's could be made to out perform the e7's in his opinion with the better combustion chamber design.
Right, because E6's flow better and make more power than E7's is why Ford switched in 1987 on trucks, Stangs, and Mark VII's. :rolleyes:
Hey, if E6's are so darn good, I've got a set (or 3) I'll sell for an all time low price of just 79.99 each! :hick:
Somewhere online is a flow chart of E5, E6, E7 and later 5.0 heads....E6 actually do flow worse than any other 5.0 head made since '69 or so. Proven.
Of course, I see in your sig you have a paxton on yours, with a little air pressure i suspect there's not a hell of a lot of difference.
Take a stock '87-'93 HO, swap stock E6 heads on, dyno it, and get back to me. ;)
torque will be down (a lot), horsepower will be sucked out of the engine, and it won't make power over 3500-4500 max.
So I will kindly disagree with your machinist, in regards to stock E6 heads being superior to stock E7's.
I have read that the E-7 heads are where thew extra 20 HP came from when the HP rating went from 200 to 220 back in the day.I could feel the difference between the two when I swapped the E-6's for the E-7 heads ....granted,my E-7 heads were ported and had a nice valve job and better springs.
Ok Normally I dont do this BUT there are some factual errors here.;)
1. trucks never used E6 style heads
2. Mark Vii's didnt even use HO engines till very LATE 87
3.E5s and E7s are near identical
4. 86 5.0 was only rated at 15lbft less torque than 87 up (not "a lot") less
5. all 5.0 HO engines are rated max hp @4000 rpm factory.
6. Flow charts really dont mean squat ..dyno results do (this is just my opinion )
7.t.birdsc was relaying a certain machinists "opinion" on a starting point for head work and that said machinist feels he can achieve better results with the high swirl chambers on the E6s
Now with all those points being made
here is my "opinion "
E6 and E7 heads are not much more than boat anchors compared to GT40s and the aftermarket selections out there , personally I could not justify swapping E6 heads for E7 heads because the gains would be so minimal in relation to the effort involved in labor .
If I am swapping heads it is going to be for WAY more than 15 lbsft and 20 HP :D
I got two sets of e7te heads laying around,roller block,cranks,roller cams,spyders,rollers,dog bones!!! pretty much worth nothing to me!!!!
So pistons ho pistons couple aods. taking up space!!!!!!
I really would not worry too much about either head. If you shooting for power, and RPM, why shoot yourself in the foot with stock heads? I'll be new springs and hardware could make a ton more power if properly matched.
well i can tell you this much from experience.. a .540 lift cam does NOT like SO pistons LOL