Hey guys, Got a question for you smart ben there done that guys?/ Anyways I have 69 Oldsmobile Cutlass "S" It currently has the 455 rocket but Im in process of rebuilding a 350 rocket...w the following casting # 395558 which I believe from my research is of the most valuable blocks alive due to high nickel quality back then and thickness of the block.. The following heads are #5 397742 which I believe as well are of the most valuable?? BUt I just ordered a rebuild kit thru Northern Autoparts which I like the quality of parts and at decent prices too... Pretty much went stock psitons but .30 over & premium rings high vlume pump and performance cam w the following specs int496/520 @50 int224/234 good for 2500-5500rpm somewhat of a radical idle.. I believe I read specs off in correct order?? I mean those are the specs and the lift is 496/520..When it comes to cams Im still trying to adjust the lingo and how to understand them... I have stock Th350 trans no stall w stock gears I believe, Im looking into 3.73... Im installing hurst quater stick as well set of headers w 3in exhaust and I also have edelbrock performer intake....I guess my question to you guys is w the lift on that cam can my heads handle wout machine work possibly just upgrading my springs?? Anything else you guys might suggest on this build:??

 

If you do a lot of freeway driving, 3.73's will be hard to drive 60 or more.
3.42's would be better and you, for sure need a Hi stall

Gene

 

I have 350 with flat tops thats almost done along with 6 heads im considering selling. just putting that out there. heads where done by rocket racing.

 

Unless those stock pistons are flat top, you will be at 8 to 1 compression or less. The Speed Pro, Probe or CP flat tops will be much better, mid 9's to low 10 to 1compression depending on measurements. Big valves, extensive porting and milling will be needed with that cam, along with at least 9.5 to 1 compression.

 

SOme freeway everyonce in awhile ya// so I might take that into suggestion thanks...

 

Hey that would had ben awesome if I hadnt put 900 in this motor already lol. how about those heads?? how much??Im on a budget this time...

 

No they are dish pistons...and about another 400 for forged so I stayed w stock..But I read those head stock valvetrain can handle decent lift stay under 5 i even read 520?? So I stayed around that and was hoping jujst to upgrade springs wout machine work??

 

the whole top end is pretty much a package as the intake has been milled to fit the heads and it has maybe 5k miles if that on the heads i have roughly 1500 into the whole package thats pushrods,guied plates , roller tip rockers, 1200 is about as low as i"ll go. it"s got bigger valves 2.072 intake and 1.63 exhaust. i really wanna sell the engine as a whole package as im looking to go 455 in the future.

 

That cam needs compression btw.

 

I think what he's concerned about is retainer to guide clearance, and if he'll have trouble with stock seals.
I'd have the guides cut for PC seals just to be safe, and not worry about it.
I think Coppers heads are already done that way, knowing RR.

 

The stock valve spring will not handle the lift of that cam.That cam sounds like the Lunati Bracket Master,or the Edelbrock Performer RPM cam.The was a spring kit that I bought from Crane,that worked well with cams like that,but not sure if it is still available.It was inexpensive,but effective.
You will also need to address that stock rockers,if you plan on running tham with that cam.You will need to elongate the slots,to give enough travel for the exhaust rockers.Crane also made an inexpenive stamped steel rocker kit,but again,I don't know if they are still available.they looked almost identical to the stocks,but had steel bridge straps,and would handle more lift.

 

I have the same casting number and I never knew there was a different from that number or any other number of the 350 blocks up to 1973. What makes this casting number so different? So if you have a block with this casting number vr a block with out it will the block with this number be a better motor? Sorry to hijack your thread just never seen that before. Can you point me to where you saw that?

 

Second what Brian said about rockers. It's hard to get a good valvetrain setup with the stock rockers. My personal preference for cheap 'n cheery is the comp roller-tip setup. Direct bolt on, clears valve covers, easy to set up. Switch to poly locks and you're done.
Also double check your final combo and the compression as noted above. Don't take the piston manufacturer's word as they tend to assume the thin shim head gaskets - you need to do the measurements and the math to verify. For a street 350 that cam will be a challenge - the tuning will be a bit touchy, idle will be rough, vacuum will be low, and it'll need 9:1 or higher compression, so now you also need to be extra careful about pinging. All this is fine as long as you're planning for it.

Do remember that the entire drivetrain is a package and needs to be matched in order to perform well. I think the engine build needs a little more attention, you will need a 2500+ stall converter. I have a temporary install with a 2.73 peg leg and it either bogs the engine or spins the wheel through 50mph. Also look into tires. the only 14" tire I can source locally appears to be made from rocks. No traction at all.

Doomah: that's probably info from the 442.com faq. Supposedly the earlier (pre-70?) blocks were thicker castings and had higher nickel content. I doubt it makes much of a practical difference unless you're trying to get an absolute maximum overbore.

 

Awesome Info guys thanks..Ok so I called my kit provider back this morning and put my order on hold..I can mix and match or add and subtract parts from this kit....What is a good cam w stock valvetrain..I would like nice idle good torque and and throttle response...Is it true i can stay under .5 on this stock valvetrain??What would b some recommendations now that I have backed off w that cam??How do you think I should proceed! I took my kit back down to stock around $523..Im looking to stay around $900for just engine build??


Doomah yes 442.com **** blocks heads etc... google does wonders lol..

 

There is no need to go extravagant with this build as it is my first so Im learning, but I would like to do it right.. Alos Im going to be replacing this 350 in return of my 455!! So I dont want to feel a huge power loss!!!None at all if possible??

 

Who's pistons are in this Kit ?

TRW ? Are they a true flat top piston or do they have a dish on top, flat top is what you want, dished pistons are low compression pistons.

That cam will run with either pistons, the flat top ones would run better.

 

A die grinder with carbide bur will elongate the slots of stock rockers easily. I have used stock rockers successfully with high lift and fairly stiff spring pressures. NHRA stockers have run 500 lb open pressures with stock rockers, but they get less durable with that kind of pressure and aggressive lift ramps (cam profile).

 

The only dish piston I would consider is the 6cc Speed Pro forged piston. You can only get the 23cc pistons in cast in those kits, way to low on compression.