generalmopars

hey all. I just rebuilt my 70' 350 4bbl to stock specs and stuck in a jm 20 22. the motor is fully assembled on the stand but the valve covers are not bolted on yet. i bolted the stock rockers and bridges on and shortly found out i would need an adjustable rocker set. i called mondello and i think they wanted more than $300. is there any other company that makes what i will need? im also open to suggestions on how to adjust the new rockers as i never used adjustables before. thanks.

Olds64

Why do you need adjustable rockers? Valve lash on an Oldsmobile is hydraulic.

FWIW, I installed the Comp Cams roller tip rocker arm kit on my 455. Here is the small block kit:

https://www.summitracing.com/parts/c...ake/oldsmobile

edzolz

This kit is for 3/8 studs, small blocks are 5/16 bolts. Are you really sure you want this kit? If you do this with your heads off the engine it will be a whole lot easier. You will have to have your heads drilled and tapped for that size and buy new studs.

80 Rocket

The part of the stud that screws into the head is 5/16". The top is 3/8" to accommodate the rockers.

Olds64

Thanks for the info Ed. I wasn't aware that the SBO used a 5/16" stud. I installed the kit on my 455 while it was on the engine stand.

I'm sure there are plenty of other kits out there.

generalmopars

well im new to building these engines and from what I was told if i go over .500 lift with the cam I would need to use an adjustable kit, my cam has .496 intake and .520 exhaust. iv never used an adjustable set before so im not exactly sure how to set it up. thanks though I will look into the comp. does anybody know if I am alright with the factory springs or will I have to upgrade them aswell.

lemoldsnut

supercarsunlimited.com is also a good source for Olds mechanical parts. Olds is all they do and Greg is a great guy.

Olds64

Your machinist can check the condition of your springs. It's mostly one of those MAW things when rebuilding your engine unless some of them are bad.

ELY442

Give this guy a call 805-975-8601, mon-sun (oldsrocketparts)

TripDeuces

http://realoldspower.prophpbb.com/topic1092.html

generalmopars

whats MAW?

generalmopars

will do. thanks

lshlsh2

MAW= Might as well

It starts the slippery slope to a frame off resteration. You know start with somthing small and might as well do this, then that turning that small project into something major.

generalmopars

lol gocha I know how that goes. I know somebody somewhere is going to hate me for this car but... a few years ago when I was a senior in high school I took the body shop program, I took my 79 T top Cordoba in to scuff it and make a color change, that's it right. with in a month the car was completely striped to the unibody and I was fixing everything hah.

generalmopars

thank you very much. just got off the phone with oldsrocketparts. WAY more courtesy over the phone and didn't try to upsell me a metric screwdriver to install muffler bearings. im going to them from now on. funny to find out that they sell the same products with out monopoly prices.

Fun71

Many things to consider here, so bear with me and please don't hate me for posting this.

• You say the engine was rebuilt to factory specs. Did you use the L2321F pistons with 6cc dishes and the correct compression height? If not, your engine is likely not at the factory compression ratio. Aftermarket cast pistons are all short on compression height, and the readily available pistons also have too-large 24 cc dishes which puts the actual compression ratio in the high 7.xx to low 8.xx range unless a lot of machining is dome to the block and/or heads.
  
  
• The JM 20-22 camshaft has the following specs:
  0.496 / 0.520 lift, 300°/310° advertised duration, 224° / 234° duration @ .050" lift.
  
  
• If your engine has low compression due to the above conditions, that cam is way too big and will not have much low end power (engine overcammed).
  
  
• You should ALWAYS use valve springs that are matched to the camshaft, and always replace 40+ year old factory springs as they are likely worn and won't allow the engine to rev without floating the valves.
  
  
• You may not need adjustable rockers, just a different length push rod. After an engine rebuild, you should use a checking push rod to determine the correct push rod length. Machining the block deck, milling the heads, using a camshaft with a different base circle diameter than factory, and different thickness head gaskets can all contribute to needing a specific push rod length.

MDchanic

I didn't see it explicitly stated above, but, as a rule of thumb, do not deal in any way with Mondello Performance Products in Paso Robles, CA - Before his death, Joe sold his business to these guys, and we see repeated posts on these boards from people who were screwed by them.

On the other hand, his son Bernard runs Bernard Mondello Racing Enterprises in Corona, CA, and he is 100% alright.

- Eric

generalmopars

ahh Ive heard of people making that mistake putting dished pistons in like that. I will explain the whole build. I did this on a budget so here goes.
i have a 70 4bbl motor that blew the timing chain at 91000, it was always very well maintained and the crank case was spotless inside but it had a lot of short run local driving (prob what killed the chain) now i bought another 70 2bbl motor that was a good core motor. i used the 2bbl motor for the rebuild. i hot tanked the block, gave it a quick hone, did all new bearings, rings, gaskets, and i stole the pistons and intake off the blown chain 4bbl engine as the pistons were the flat top style and were in real good shape. as for head gaskets i used the blue felpro types, if that helps. please don't slap me too hard for honing & swapping pistons. i know if i had the money i would have bored and bought new slugs. whats your thoughts?

generalmopars

yupp im now an EX Mondello customer

Fun71

OK, so you reused the factory 350-4bbl 6cc dish pistons. Those have the proper compression height, so all you really did was replace the ~.018" thick metal shim head gaskets with ~.040" thick composition head gaskets. My calculations show that should put you just above 9:1 compression ratio, depending upon the actual combustion chamber volumes and piston-to-deck clearance (I calculated using 68cc and .020" but your actual numbers may be different).

That may be a bit much cam for the compression ratio but it's definitely a lot better than I originally thought it was.

generalmopars

hah thanks I guess lol. yeah man when I took the heads off I was like you got to be kidding me, I had no idea the 2bbl used those big dishes. I bought the 70' specifically because I figured if I swapped the intake I could have a factory 310 out of the box but I was wrong. I know this is getting off topic but is there really any difference between #5 & 6 heads?

MDchanic

One is a year or two older than the other.

- Eric

tru-blue 442

#5's are 69, #6's are 70. Both are good heads. I think 5's may be 68 also?

MDchanic

5s are '68, too.

- Eric

tru-blue 442

Thanks Eric, I'm not to up on the small blocks. I had a 70 S w/a 350 that ran great
and a 67 330 C/S 4 speed that ran like a scalded dog with #4's.

oldsmobiledave

Too much cam. Talk to Mark aka CutlassEFI for an Erson grind or go with a JM 18-20 if you are committed to an Engle cam (Mondello JM cams are reboxed Engle cams). Your stock springs will be fine with the 18-20.

What is you location?

generalmopars

ya see its a funny thing, I wanted to go with the 18 20 but lynn told me over the phone id be better off with the 20 22. I figured well hey they cost the same, so why would he bs me right. now I just talked to oldsrocketparts today and they said lynn was probably out of the 18 20s and pushed the 20 22. now the whole motor is assembled ( valve covers are off still ) and im past the point of no return. i just hope it runs decent in the end. i forgot to mention i built this motor to replace a severely worn out 307 for my 1990 buick electra wagon.

generalmopars

i know 5s are 68-69 and 6s are 70 its just everywhere in history ive always heard everyone praise the 5s but never include the 6s and to my knowledge the 68-70 engines are the same. im not sure on this but i think the 7s and 7as are the same just with hardened seats. let me know if ive got that wrong please

MDchanic

I doubt you could tell the difference between 5s, 6s, and 7s in terms of combustion chambers and runners.

6s, 7s, and 7As did have variations in valve spring pocket depth, with 5s having shallow, 6s having intake deeper (for a rotator), and 7s having both deep (for 2 rotators), if my memory holds.

Oh, and do what these guys say with the cam - it's a lot easier to swap it in now than to do it later when you really hate the way the car runs.

- Eric

Fun71

The 2bbl engines had 14cc dish pistons. Those are small dishes compared to the 24cc dish volumes on the commonly used "stock rebuild" pistons.

oldsmobiledave

While the engine is still on a stand you are far from past the point of no return. Do the cam swap now. The JM 20-22 will be easy to sell to recover some $. You can buy direct from Engle.

You never mentioned your location.

generalmopars

sounds like you guys are pretty confident in this cam not working out. damn... ive got some thinking and strategizing to do. im from Harrisburg pa btw

generalmopars

wow really, that's absurd. i thought the 2bbls were bad. wonder how many people made that mistake.

generalmopars

i appreciate the advice i can tell you guys are steering me in the right direction. im alittle upset with lynn to say the least

MDchanic

Without saying anything downright libelous, if you search this board, you will find many first hand accounts of people who describe behavior on the part of Mondello Performance Products that most would describe as criminal or bordering on it.

- Eric

generalmopars

yeah the guy at oldsrocketparts filled me in on some of what goes on at mondellos. they shouldn't even be aloud to run a Renault or Peugeot supplier. hey how do you get your name to always show up at the bottom of all your posts?

don71

Go to user CP, upper left of screen... Look for edit signature. Or, in your case make a signature. It can be words and a picture too.

Good luck with your project.

generalmopars

cool & thanks.

MDchanic

I just type it.

- Eric

80 Rocket

455s are 5/16" as well. Unless you have A heads. As I said, the Comp Cams kit you mentioned will work well for the OP application. The part of the stud that threads into the head is 5/16" with the Comp Cam kits.