So I have had this engine for quite a few years and finally got around to tearing it down for a rebuild. I always assumed it was a stock 302 with an Edelbrock intake and Carter Carb, so I was surprised when I opened it up and found some extras. I am hoping that someone can give me a rough estimate of the horse power and torque the engine may have made when it was running.
Here is a list of the combo:
-Stock 71 302 Block
-Stock 71 302 Crank and Rods (3" Stroke)
-Sealed Power Pistons and rings. 273AP (.030 over)
-DooE 351 Heads (60.4cc) 1.84 Intake, 1.54 Exhaust
-Edlebrock performer 289 intake
-Carter AFB 650 carb
-Mallory Unilight ignition (Mechanical Advance)
-Isky Cam #381280 hydraulic
-RPM Range 2500-6500
-lift .467 Int .467 Ex
-lash .000 Int .000 Ex
-Adv Duration 280* Int 280* Ex
-.050 Duration 224* Int 224* Ex
-Lobe Center 108*
-I calculated the compression ratio to be around 10:1.

The engine is going into a 1971 Ranchero. Im not planning on taking it to the track, really just use if for a daily and some light towing. It is going in front of a zf 5 speed and a 9" with 3.25 limmited slip. Does anyone have any suggestions for what components to keep and what to change?

Thanks.

 

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Sorry I was in the middle of writing the post and my kid pushed the enter button and posted before I was done.

 

I hate it when that happens...................................What you basically have is about the equal to the 93 Cobra 5.0 (235 hp/280 tq) with a little less HP/TQ (the Cobra would best due to the roller valvetrain) If the heads do not have hardened seats, now would be the time to do that if you're going to use it as a daily driver. Screw in studs and guide plates too while they're at the machineshop. I would upgrade the intake to an RPM or a Weiand Stealth (take your pick these two are about equals) Or one of these: Shelby "Cobra", Ford A321, C9OX or Edelbrock F4B (again all these are equals too ) If you're going to bore it, then it would do you well to stroke it too, giving it way more torque.

 

Reasonably priced 5 speeds are hard to find. Thank god for the ZF! However... a 302 is kinda weak to be in front of the zf. For a DD/lowes machine it should suffice. The zf will have a pretty good power loss from flywheel to the rear. Add on top of that, the 302 doesnt make the best low end torque, but the 5.72 first gear does help. You said you are not that worried about it, but there is a difference between not a hot rod and wheezing boat anchor.


Boring and stroking is nice and dandy, a 347 is a beast of an engine. Or get a windsor and the money that would be used for a stroker kit, get a set of aftermarket heads. Because we all know ford heads suck.

The .76 od on 3.25 gears with 28 inch diameter tires comes out to 1630 rpms at 55 mph. 30 inch tires is 1522 rpms at 55 mph. Seems a bit low. Isnt the rule of thumb around 2k rpm to keep oil pressure up?

for durability, fuel economy, and usable torque..... The straight six guys have me sold the 300 i6 being fords most perfect engine. But that would mean giving up the music a v8 makes. And thats not going to happen anytime soon.

 

I missed the part about the ZF in a Ranchero, pretty sure that's not going to happen without major floor surgery. And not without lifting the car too, the ZF hangs down about a foot below the main shaft centerline. You need to stick to the car type 5 speeds for a Ranchero.

 

Overall, it's a bit hotter than a stock 302, though year depending. Right on par with stock late 80s ones peak power wise (flywheel). The torque curve is a lot stronger.




I put in the specs on Desktop Dyno and it came up as (flywheel numbers):

312hp @ 5,500rpm
334lb-ft @ 4,000rpm

The curve is very different than stock, where it dies off at about 3,800rpm so it should have pulled a lot harder. The numbers I'd say sound pretty close for flywheel figures, especially since I had the flow bench numbers for stock 351 DO0E heads. I couldn't tell you what it'd be at the wheels because I don't know what it was in or it's drivetrain. I'd be willing to be about 40-50 less of each of those numbers for an automatic and about 20-30 less in a manual.


With a .030 overbore it gained a little lower end horsepower and about 4 lb-ft of torque overall.


I also have flow bench numbers for ported but otherwise stock 351 DO0E heads. I went ahead and ran that as well with your current 1.84/1.54 valve setup. Remember, these are flywheel figures. Actual rear wheel figures will be much less.


346hp @ 6,000rpm
349 lb-ft @ 4,500rpm



I also got a bit curious and put in a set of 1.94/1.60 valves to see what it would do. Remember port velocity is what makes power, not just big valves. Power boosted up to:

349hp @ 6,000rpm
350 lb-ft @ 4,500rpm

It might not seem like a huge gain in peak figures, but the valve change made average horsepower increase so your overall range is around 335hp. I'd say that's pretty damn good.






TL;DR

Leave the engine as is and refresh it. For a decent gain in power, I'd home port the heads with a $30 die grinder and have the valves upgraded to 1.94/1.6. Doing this, Desktop Dyno is estimating an increase of 37 horsepower and 16 lb-ft of torque. I'd say that's a pretty good tradeoff.





It's a pretty nice setup. I'd leave it as is and just refresh what it needs. It will have plenty of power how it is in that Ranchero. Also, if you go the home porting route, there are guides all over the internet on how to do this.

 

Those numbers aren't going to happen with the list of parts he listed. Not with that cam, intake and the heads either.

 

See flywheel horsepower with open long tubes. Pipes with mufflers will drop that 30 horsepower easy. Drivetrain loss should set him into the mid 200s at the wheels. Still want to tell me its not going to happen? Because iirc, I said it was a bit hotter than stock but the range was better and stock motors that are in decent shape tend to dyno right in the range I listed at the rear wheels.

Similarly, my friends Mustang II has a '84 302 with nothing but a ***** Thumpr cam, intake, custom headers and a 4 barrel, and I watched it lay down those numbers right in front of my. Again flywheel with open long tubes. Sure feels like that too when he gets on it.

 

Really ? An 84 302 with 8 to 1 compression and huge 70 cc chambered heads is going to lay down 325 HP ??? With no other changes that a thumper cam and (what) intake ? I've been wrenching on these things for 35 years, it's plain to me you just got started. This is amusing to say the least.

 

You need to return that desktop dyno program and ask for your money back. Then start actually building the engines your advising others to build.

 

Yes. I will get the dyno sheet when I can and upload it. I was even a bit surprised myself.
I've built 3 going on 4. That said, I will admit I am relatively new to the scene. I will also say it was spot on with the 310 horse motor I currently run. Not nearly putting that to the wheels though.

 

I think you have a really good find/discovery here...especially if you are looking for a nice daily driver....
the cam is mild but much better than stock....and would say the actual power band (where tq/hp are performing best) is going to be in the range of 2000-5000/5500 rpm....depending on the valve springs....assuming they are "heavier" than oem replacements that should give you 5500 rpm with no issues...it should have a very good idle especially with the lift being right at 470...I would swag your brake hp (rear wheel) would be in the 250 range with some head porting/matching which really makes for a nice, smooth driver. IMHO, if the heads need not just a rebuild but new valves, etc, then I would look at aftermarket assembled heads...a little cheaper (most likely) and a little better performance for the $ (TrickFlow, etc...someone will have a good recommendation).....
increasing intake valve to 1.90's is about as large as you would want to go on a street engine so unless the vales need to be replaced, you are pretty close to the peak anyway in that area.......and the 351 heads, well that was a "thing to do" for a while when SoCal gasoline went from leaded 98 octane to 91 lead-free.....with the gas quality fairly well stabilized for the past few years now, IMHO, if you were going to change heads, going back to the 302 spec would be a "good thing" all with the same reasoning as previously stated.

especially in the ranchero, 5 speed and the 3.25's that will make for a really nice driver......