Thinking about swapping some 351 Cleveland-4v pedestal mount rocker arms on my stock 5.0 to get a little extra lift out of the factory cam. Looking specifically at the Melling MR888 rockers. They appear to have the same dimension as the windsor rocker arms from the pivot point to the spring pad, but are 1.73 ratio, compared to the 1.6 windsor rockers. Not to worried about pushrod interference, as I've run 1.72 ratio before on other 302/E-7 head motors and it wasn't a problem. Seems like a lot cheaper route than buying a set of roller rockers to do the same thing. Anybody ever done this before?
Engine 351 Cleveland - 4V Rocker Arm Question
- Thread starter Middleagecrisis
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That price difference is only if you buy new. I have picked up 2 sets now for around $100 CDN (about 75 US) each set. Look around, inspect the ones you find. If not damaged you can get some good deals.
I didn't pick up on it before either, but you want stamped steel (non-roller) pedestal rockers. That is a whole different debate. If you don't want the efficiency of roller rockers, why not just put in a B-cam with the stock rockers and call it a day, it will be basically the same lift.
I do know that when I mocked up a set of the 1.7 Crane rollers on my Cleveland heads, they didn't look like they were going to fit right. When bolted to the pedestal mount, the roller tip wasn't far enough onto the valve stem to remain on it through the full valve stroke. So even though the ratio is really close (1.7 to 1.72) I think dimensionally the Cleveland rockers are longer overall.
I didn't pick up on it before either, but you want stamped steel (non-roller) pedestal rockers. That is a whole different debate. If you don't want the efficiency of roller rockers, why not just put in a B-cam with the stock rockers and call it a day, it will be basically the same lift.
I do know that when I mocked up a set of the 1.7 Crane rollers on my Cleveland heads, they didn't look like they were going to fit right. When bolted to the pedestal mount, the roller tip wasn't far enough onto the valve stem to remain on it through the full valve stroke. So even though the ratio is really close (1.7 to 1.72) I think dimensionally the Cleveland rockers are longer overall.
B-cam lift is posted at .480 with 1.6 rockers, the stocker with 1.7s is .472. Almost the same without the lose at lower end and a very smooth idle.
When I reassembled my 90 GT (I got it as a rolling chassis, engine and trans on pallet and everything else in boxes or piled inside) I re-gasketed the original engine and put 1.7RR on it with stock cam, smoothed the exhaust ports (removed the casting flash and thermactor bump), put MAC equal length headers on it, full 2.5" exhaust, Explorer intakes, injectors and TB and Contour electric fans. Stock AOD with the Lentech VB and 3.73 gears. That was it. I did not dyno, but seat of pants and speed on a marked 1/4 mile piece of road makes me believe I was making 280-300 at the crank. I don't know what your goals are with your current combo but a snappy combo can be had pretty easy with some simple parts.
Used parts can be your friend, don't be afraid of them, just do some homework. Actually come to think of it, the only NEW parts I put on my stang when building were the e-brake cables, a replacement speedo cable (I melted a couple already), speedo gears, a couple aftermarket gauges and spark plugs (plus fluids and filters).
When I reassembled my 90 GT (I got it as a rolling chassis, engine and trans on pallet and everything else in boxes or piled inside) I re-gasketed the original engine and put 1.7RR on it with stock cam, smoothed the exhaust ports (removed the casting flash and thermactor bump), put MAC equal length headers on it, full 2.5" exhaust, Explorer intakes, injectors and TB and Contour electric fans. Stock AOD with the Lentech VB and 3.73 gears. That was it. I did not dyno, but seat of pants and speed on a marked 1/4 mile piece of road makes me believe I was making 280-300 at the crank. I don't know what your goals are with your current combo but a snappy combo can be had pretty easy with some simple parts.
Used parts can be your friend, don't be afraid of them, just do some homework. Actually come to think of it, the only NEW parts I put on my stang when building were the e-brake cables, a replacement speedo cable (I melted a couple already), speedo gears, a couple aftermarket gauges and spark plugs (plus fluids and filters).
I like your thinking on used parts! So far, I have a used Explorer engine (1999) on the stand that I plan on taking my time and building, a used Typhoon intake, 70 MM TB, '95 GT Mass Air Meter and shorty headers that I planned on installing on the stock motor currently in the car. I did buy a new off-road pipe to compliment the flowmasters already on the car. I have 3.27 gears now, but occasionally drive 100 mile roundtrip to work on the highway, so I don't want to go lower at this point. I've done the 1.72 Crane RRs on several motors before and know they work, just thinking about a different lower cost option with the Cleveland rocker arms. How's your shift harshness with the Lentech VB? I had an AOD built with a TCI VB and the part throttle shift would knock the fillings out of your teeth. I played with the line pressure, and it never would calm down. I like a firm shifting trans, but that was way too much of a good thing.
Only thing I would be concerned about with the Cleveland/M/460 style rockers (all the same) would be hitting the retainer and possibly knocking one of the locks off. I'd get one or 2 and try it just rolling the engine over and see. I know roller rockers with this ratio have been used on Windsor heads, but remember the tip is different between roller rockers and stamped rockers.. just my $0.02
I have not played with the line pressures as far as an external adjustment. I have only played around with the throttle valve cable. When I first installed the trans and set TV based on Lentech directions shifts were very firm but needed higher RPMs before shifts than I wanted. For example, I could not get to shift into OD until at least 50-55mph, even at low to part throttle. So cruising in town required me to speed, shift to OD then coast down, but stay above 37-40 mph or would downshift hard back into 3rd.
I backed off the TV cable adjustment and it is awesome now. If I crawl away from a light now it will shift to 2nd mid-way through intersection (quick shift, smooth and non jarring - almost don't feel the shift). and if I maintain a relaxed pace it will work through the gears and into OD without drama and about stock RPM/time. If I "floor it" from the light, I get firm snappy shifts in all gears (will chirp tires) at higher than stock RPM.
My TV cable setting is approximately 3/4"-1" of pull on the cable to connect it to the TB. In other words, if I disconnect the TV cable from TB it will sit relaxed approximately 3/4"-1" towards the firewall from TB. Decreasing this distance will make shift points and firmness softer, increasing the distance it will make it firmer.
Thanks for feedback! My AOD was rebuilt by the PO and actually shifts very crisp. The upshifts are way to early, though. I'll look at the TV cable setting.
Start with small adjustments. Disconnect it from TB, see where your current set up is and adjust it for a little more pull on the TV cable (start at 1/8-1/4" more), drive and warm up the car and see if you like it. Repeat until you find your sweet spot.
Finally got around to buying a Melling 351C rocker arm and mocking it up on my explorer engine. In summary, this isn't going to work, but I wanted to show pictures of why it won't work. Hopefully, this will answer any future questions on the possibility of swapping 351C rocker arms to get the 1.73 ratio on a windsor engine. Pic 1 shows the physical size difference, Pics 2/3 show the valve tip/rocker arm contact at no lift and full lift, with the 351C rocker arm only making partial contact on the valve tip. If this situation didn't break something, it would certainly cause rapid guide wear. No amount of shimming on the pedestal would correct this misalignment. Pic 4 shows the windsor rocker with the correct rocker arm/ valve tip engagement. On a positive note, I tore down my explorer engine after I did the mockup and it still had the factory cross hatch on the cylinder walls and no evidence of guide wear on the GT-40P heads. I was blown away how clean the motor was on the inside. The #3 main bearing had very little wear. I may just put on a new oil pump, re-gasket, add HP springs ,small cam and run it as-is until I can build a 347 with my Mustang block.
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hmm... I think I have a set of 1.7rr on a shelf, pedestal mount ect for stock heads. Ill do some digging around for them if your interested.
Well, I wanted to physically verify. I figured spending $8.00 to verify and show others the results wasn't an unreasonable amount of money to spend.
oh thats a good point... I do think I have a second set somewhere... buried
I found a company selling reground HR SBF cams on Ebay for $154. I've gone this route before and never had a problem. Looking at a cam that specs out at 214/220 .482/.496 112 CL for my explorer motor. Should be a good cam for the GT-40P heads. Figure I'll just upgrade the springs and run the factory rockers, so I can run the stock valve covers.
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