Mild 302 Build

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Rmoore45, Nov 25, 2012.

  1. Are you going to reuse the stock pistons?They should be forged but the rings are more $$(metric).If not look at what D.S.S. has to offer,they have larger valve reliefs & this opens up your cam choices(more lift).Save your money for better heads,entry level aluminum heads can be had for not much more than your 600$ budget.Check out comp cams Xtreme energy line,I believe the XE268? might get you to 300hp with the right hci combo.I would recomend comp for your complete valvetrain.How large are your headers?What intake do you have?What gears are in the car?Hope this helps you out.
  2. Save yourself a ton of money and time.

    Find an explorer gt40p engine in the junkyard (around $500), swap out the cam, change the valve springs, get some gt40p headers, put your carb and accessories on it and be done.

    Rebuilding a 302 with basic parts just isn't worth the time or money when there is a million perfectly good explorer engines out there.

    You will even be able to sell off the intake and recoop a few bucks.

    If you want better heads, sell off the p heads (worth about $200) then put that money together with your $600 and get yourself some used twisted wedges, or throw in a few more bucks and get new ones.

    Then use the long block you have to rebuild as a 347 over time. At least the block, the heads turn in for scrap.
  3. The E7 heads are not bad, and I bet will outflow most old ones. If you want a mild jump in performance, you should be happy. I had a pre roller block to 4bbl carb on a roller block and E7 heads replacement motor in a car. But even worked over, I saw tests where the various GT 40 heads out flow them easily.

    The advice above from the others is sound. I just would get specifics on the cam and your intended RPMs before I asked them for which port size to order. Beware of balances on the flywheel and harmonic balancer, or big vibrations WILL be an issue!
  4. If you want cheap heads I would say procomps 190cc 62cc combustion chamber alum.. They get bashed alot because of them being Chinese made and sometimes the casting isnt great but honestly I haven't ran one pair of heads that I haven had machined and cleaned up. I found my pair on eBay for 382$ complete then had a friend machine them... I'm running about 400hp off a 331 stroker with them so I can't complain
  5. 1.) The block may not need to be bored at that mileage. If the pistons and bores are with useable limits, I would probably just go with rings and bearings.

    2.) What intake and carb? Cable clutch, hydraulic, or z-bar?

    3.) At the crank or at the wheels?

    4.) I would be more concerned about getting a cam that worked well with the heads and induction.

    5.) You don't have to use heads from a roller engine, but they're going to be the better ones to have. At the very least they will have hard seats.

    There are going to be a lot of other little details to work out with the swap, too.
  6. Your 289 will have 3 bolt accessory drive/balancer, and 28 oz balance.
    The 302 will have 4 bolt accessories/balancer, and a 50 oz balance.
    Same with swapping the flywheel/flexplate, 28 vs 50 oz balance.

    You will obviously need to keep the 50 oz balance if you want to use the 5.0 short block.
    That means you won't be able to swap many parts over from your 289 when it comes to accessories.
    You'll need to swap to 5.0 serpentine stuff (reverse flow water pump), or find 4 bolt balancer compatible v-belt pulley stuff that is also compatible with your 289 accessories. Not hard to do, but you need to know about it, and then avoid little pitfalls like water pump inlet locations, direction of belt travel vs water pump, and timing cover compatibility. Lots of little stuff to plan out.

    You can use any head on a roller block, however, the pushrod lengths will change.

    You also have the choice of the 69-73 351w head. The best iron head from the factory, and on par with many aftermarket heads when ported.
    The P-heads are in the same ballpark ported vs ported, but you have to worry about header fitment with the relocated spark plugs.
    On the other hand though, the P-heads will work with pedestal rockers (think budget), while the W heads will require machine work to adjustable valves and guide plates, no ifs, ands, or buts. (think extra money) So there are drawbacks to either. The buy in price for W heads is cheaper than P heads. Just things to think about.

    The roller cam may also need a different distributor gear drive. So do and some don't. It all depends on which cam you use. I haven't kept up with the details on this. Used to be that all roller cams needed a different distributor gear, but I think that is changing depending on manufacturer.

    If your car is old school manual tranny, the equalizer bar will need an adapter as the 5.0 blocks do not have the bolt boss on the side to mount the equalizer. I have seen adapters that bolt to the bellhousing bolts and provide an equalizer mouting point. If you have P-heads at this point, and you are probably familiar with the pipe routing on 289 headers for manual trannies, I doubt very seriously they would work with the plug placement on those heads.
  7. Threads merged together. :)

    Clayton, do you want it to remain here in the 5.0L Tech section, or would you like me to move it to the Classic Tech section. Your choice.
  8. Summit racing(
    Pertaining to roller cam compatability out of the box,Dizzys are available from MSD & Summits private lable brand(made by Mallory).
  9. I would prefer it in the Classic Tech Section since this is going to be a motor for a classic mustang.


    btw the Hulk avatar is cool:cool:
  10. I don't have any advice, but I'm eager to watch this build. It sounds awesome!
  11. Mr. Hulk, Sir,
    This also applies to any early V-8 Fox body. The 28/50 oz balancer and flywheel issue is exactly what I was thinking about in an earlier post. What is the year of the switch??? Do not let your Chevy mechanic or builder buffalo you into using the wrong parts - the motor will shake like California on a bad, bad day. I won't do that again. (I found out they took "coffee" at the bar by 10 AM. No one told the new guy in town until I had troubles.)

    I may withdrawl my advice on the E7 heads. I caught your power goal this time, and you will likely have to up the compression old school style, do porting, have a healthy (maybe even squirrely) camshaft, a single plane intake (if with a carb), and have some RPM to make this number range. With inexpensive but good heads available (that were not so easy to get when I did the swap), I think you will be happier to reach your goal aftermarket style. Lower RPM cruising and power is more fun for a non track car. Mine is as high strung as this motor described. It's loads of fun from 2000 rpm up, but it's cold blooded and I hate when I have to go slowly in it. SLipping the clutch that much and trying not to leave black marks in front of a school gets old. It is just not a happy car unless the tires are spinning or it is going fast. Besides, the 25-50 lbs weight savings off the front compared to iron Gt-40 or E7's is not a small amount to consider in a small car.

    Good luck and have fun!
  12. Update

    I bought some cleaned,painted, and rebuilt Gt40 heads off of eBay from a reputable seller with good feedback. I told him that I didn't want the valve springs or rockers because I don't need them and got him go a bit lower on the price. I went with the Gt40s because I didn't want to have to worry about my current headers not fitting with on the P heads. I'm also going to try and port and polish these heads while I'm saving money to buy other parts. One more thing, I'm going to measure the combustion chamber of these heads so I can figure out my compression ratio.

    As for the 50 vs 28 imbalance thing I have figured it out. My 289 is a 28oz imbalance motor, my 92 302 is a 50oz imbalance motor. When I changed over from a C4 to a T5 I planned ahead and got a billet steel flywheel with removable weights, right now it has the 28oz weight on it, all I have to do is swap it out with the 50oz weight and the flywheel is done. I did some research on the harmonic balancer and found one on summit that is for a 50oz imbalance motor and has 3 holes for my crankshaft pulley. Problem solved.
  13. What size clutch does your solution allow? I think it stepped up a half inch in the process to 10.5" when I did it.
    Let us know how the heads turn out.

    This is what I am seeing for the 28/50 oz stock switch over answer - but this is second hand info for those wanting used parts. "The 5.0 was introduced in 1982 when Ford decided calling 302 a 5.0L when they went metric system. Roller type did not start until 1985."
    As far as the 3 or four bolt balancer/pulleys, I'm glad you got what you need.
  14. I went with a king cobra clutch which is 10.5". It does not feel like a stock clutch at all but I eventually got used to it.
  15. 1.) The T5 only has room in the bell for a 157t flywheel which will only take up to a 10.5" clutch.
    2.) They didn't "go metric" so much as simply adopting the metric naming convention. 5.0 engines used fractional dimensions throughout until 2001 when it was dropped completely.