So... I as I am gathering parts and pieces to build the 324 for my '29 tudor, I am looking to get some guidance and input on a few particulars. I am not a mechanic, but understand that these are things I need to know and should get a handle on to ensure my choices on parts will result in meeting my expectations for how the car performs. Some specifics to start are that I have a '56 324 block, '55 #8 heads that will be opened up to '56 port and valve sizes since I haven't been able to get my hands on some #10's, McGurk 1.5:1 adjustable rocker arms w/ corresponding early rocker shaft brackets/stands, an Engle solid roller cam, Weiand 2x4 intake, Mallory YC distrubutor, and I will be using an adapter and 4spd manual trans. Now... With those particulars out of the way, I am hoping to get a few unknowns figured out. The first being more info on the cam and what to expect from it. The only info I can find on it are as follows from the 1964 catalog: Engle Solid Roller; Grind 238; Short Duration Competition; Exhaust timing: 68-38 Intake timing: 38-68 Duration: 286 Lift:440 Settings: Intake - .013 Exhaust - .015. I do not have the original cam card so I don't know the lobe separation or anything else. The Second thing I am hoping to determine is, what compression ratio I should be targeting with this cam? The third question is, with all of that tied together, and assuming the tudor will be used mostly around town and occasional interstate trips, I am stuck determining if a wide (2.56 1st) or close (2.20 1st) ratio 4spd should be used, and what rear dif ratio to go with? Now, before it comes up, I have used the online RPM-Gear Ratio-Speed calculators and got some general ideas of all of those (assuming 29.5" rear tire)... but without knowing what to expect from the cam and it's relation to the Old's stock 240hp @4400rpm and 350ftlb @2800rpm, I feel a bit stuck. So I am hoping for some insight and maybe some answers. Thanks in advance!
The lobe separation for your Engle is easy to figure because it’s a single pattern cam, IN 38-68 and EX 68-38. 38-68=106* + 180*= 286*. Divide 286 by 2 and we get 143*, subtract the intake opening figure of 38 and we have 105* which is the full lift figure. The single pattern grind gives the same value for the exhaust, 105*, and that is your lobe separation. 105*+105* = 210/2 = 105*. If the grind was a dual pattern cam, like 38-68 and 74-32 then we’d have 74+32=106* + 180*= 286*. We still have 286 /2= 143* but the EX closes at 32* shifting that full lift event to 111*. Now add the IN c/l of 106* to the EX c/l of 111* and we get 217*/2 = 108.5* of lobe separation.
That "short duration cam" will help for street & cruising. Watch the water temp close, or the super-hot oil can anneal those Rockers. Valves keep opening-up their clearance settings. May need to opt for adjustable Pushrods. 2:20 low has a nice Second-gear with a 3:43 or 3:63 Ring&Pinion. 56 Olds was 356, late 52 to 55 was the 324. Get that Mallory distributor looked at, most had no Vacuum advance, can be problems on the street.
Thanks Fordors! With that known the only piece of info that I would be missing that would have been on the cam card is the duration at .050. Thanks for the recs, I have never heard this about the rockers in particular. The tag on the distributor is YC-250 C. YC indicating it is mechanical advance only (ZC being both mechanical and vacuum). I am debating running it as is on points or trying the Petronix kit in it. Done quite a bit of digging around here for info on that conversion but seems like the decision is still out on whether its a worthwhile upgrade as some people get bum units.
I assume you plan to use a T10 4 spd trans. Yes both 220 and 256 first gear ratios were available in mid 60's. Ford T10 had 236 low gear, not hard to adapt to a GM engine. I would not use one with 220 low gear, a real dog if axle ratio is in the 3's. These old T10's are now hard to find. I would do lots of research before installing a roller cam. Make sure cam is compatible with 1.5 rockers. I would use a flat tappet cam with real #10 heads, believe result will be more performance & fewer problems. Those #10 heads are out there. Be patient & keep looking. This from a real Rocket lover speedshifter Greg White
Thanks for responding Greg. I actually had to search out and find all the 1.5:1 rocker parts just because of the cam. Engle catalog specs the cam to only be used with 1.5:1 rocker arms and that's what it was originally sold with as a kit. I have a line on an '64 M20 locally and same may have an M21 I just need to figure out which would suit the motor and car better. I've been sticking to GM 4spds since the bellhousing adapter is B-W bolt pattern. If memory serves (and it rarely does) the wide ratio T-10 for GM's was also 2.54 and the close was the same at 2.20. So I'm needing to decide between 2.56/54 and 2.20. Seems like a 2.56 or 2.54 M20 or T-10 would fit my needs a bit better?
I have a wide ratio t 10 which I prefer,the close ratio. I think the gears are to close if this is for a street driven car.
Consider this option for the distributor, one that Tony uses at Ross Racing. Use the Mallory as the trigger for a MSD6al unit. Good option, lots of them out there working well.
Thanks for the hot tip! I need to get some guidance and a quote on some other tid bits for the 324 like pistons, lifters, and a timing set, so I'll add that to the list. Anyone with some input or knowledge on whether to bump the compression up? down? keep it at/around the stock 9:1? It seems the trans is leaning towards the wide ratio... times like this I feel like DON_WOW would have had some great insight regarding how the cam would play with the trans ratio... anywho... with the wide ratio and cam would rear dif around the lower/mid 3's be a good all around choice?
If you're going to go with a 4 spd, I'd go with the wide ratio trans with a 3.42-3.50 rear end gear. Model As have large rear wheel openings and need a tall tire to fill them and look right. A 2.20 first gear will feel real lazy from a stop with tall tires and a highway friendly gear. I would call Tony at Ross Racing Engines or Lanny at LTR Racing Engines (Onyx, California) with your engine combination questions. Both have built many Olds rocket engines in the modern era and can give you real world advice. I too collected a bunch of old Olds engine parts but after a couple consultations I ended up going with all new modern internal parts.
assuming a 29.5 inch tire, and a 4 speed, I would want the rear gear no less than 3:50. I have 3:50 gear in my 39, it has a 29.5 inch tall tire on it and it performs great. I will be doing a very similar combo to yours in my 32 tudor, 324 olds and 4 speed, I'm planning on a 3:63 or 3:70 gear in it, it will also have 29.5 pie crust slicks from Towel City tires on the rear, but a little steeper gear will make it better when the 7.50 16 tires go on for cross country driving.
OP, I forgot to mention that one of your options with the 324 is punching it out to 4 inches and using standard 371 pistons. This will give you a 345 ci engine. Oil to the top end is always a concern with the Olds engines. We all remember the classic rocker arm rattle common to older Olds engines, much of which was contributed to old oil make up and sludged out engines. I do not run a roller but rather a cam from Tony with Chev hydraulic lifters. He recommended using GM hollow push rod on the ends of the valve train to assist with oiling. So far it has worked well.
Thanks much! I plan to call Tony soon. I'm glad you pointed out the CR performance as it relates to highway friendly gearing. Definitely a fine line to balance the give and take. Jason I appreciate the input! The rear ratios you mention are pretty much on the nose of what I am considering. I am wondering though if the 3.70 range would spin to high an RPM on the freeway or relegate me to the slow lane with gramma? I'll be spinning just under 3 grand to pull 70mph. With 3.50 I'll get at least 60 at 2500 which is not that much more than my modern pick-up. So I'm feeling much more comfortable on the 3.40-3.50 range on the ring. Thanks! I have debated punching it out to 4" and using 371 pistons, but I know once you go out to 4 those walls start getting a bit thin and thats pretty close to the end of the road aside from just putting a hone in the tube. Not sure I am ready to go down that road yet. As to the push rods, from your experience how does that work? Do the gallerys in the lifter bores pump the oil up through the lifter, through the push rods and then..? I know the rockers oil through the gallery in the head in to the pinned rocker stand, in to the rocker shaft and then in to the rocker arm.. is the purpose just to get more oil in to the rocker arm/pushrod interface? or is it to just feed more oil in to the rocker assembly from both ends?
I had the block sonic checked prior to using the 4 inch pistons. Mine is a '54 block. Might have more to work with than a '56. Always best to check before committing. The push rods on the end of the valve train receive their oil feed from the hydraulic lifters which with a roller cam assembly you won't have. These four just add additional oil to the top end to assist with the normal oil feed through the rocker assembly. Anymore than the end push rods would certainly flood the valve cover.
My '56 324 went to 4", no problem. I had some 4" NOS Jahns pistons that I wanted to use but they were going to be 11:1 and there wasn't enough meat anywhere to remove enough metal to even get to 10:1. So I ended up with Egge 4" pistons. OP29, do you have access to an old Engle catalog? I have an Engle 151 roller cam and would love to know the specs?
Bob, this is a page from the 64 catalog. The 151 is for a blown engine and unfortunately no specs outlined. States specs are provided with each hard faced overlay cam. I had a Chet Herbert roller several years ago with no cam card. Ross took it and profiled it for me.
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