Smog 72 350. Getting 4 heads, but w felpros. Comp should be sub 8.5:1. 650 vac sec. carb, 1" open spacer, performer intake, 4-1 headers, x pipe, flows.

Stall is stock, tranny is th350 for now, gear is 3.42

Stock .400 72 2bbl cam now.

Car is heavy ish, has ac ps power brakes full interior

Getting a good grind for an olds is important to me, we'll be going through delta camshaft in Tacoma wa. Anyone do business with em?

I'm not tryna get a lope, just trying to take a bit more advantage of the exhaust and gears without going too big for my bs compression ratio.

Thoughts?

Goal would be 14's and daily driver status.

 

Decided previously purchased mondello JM 18-20 is too big

 

I would talk with (cutlasefi) here on the board. He can grind you the cam you need to fit your build and is fairly priced and knowledgable with olds motor

 

Well delta is local, been in business here for over 50 years. Would love his input however.

Plus the can kit from delta is 125$. Deals!!

 

i second this.. very reasonable, knowledgeable about Olds cam characteristics...

 

I'm also wondering if a smog 350 and 14's is gonna happen. Nonetheless still would like a good mild cam for the combo

If he chooses to add wisdom to the discussion I'm sure it'll be pure gold I've read some of his posts

 

Honestly some of the olds cam stuff has been gone through so its expected to see some additional exhaust lobe to crutch things, what im interested in beyond that is how the exhaust mods play in and if playing with the timings could build us some dynamic cr

 

Additional exhaust lobe doesn't necessarily "crutch" things. More lobe duration opens the exhaust valve sooner and adds more overlap (provided the separation angle stays the same). A shorter exhaust duration will typically add torque, as it holds the charge in the cylinder longer during the power stroke before exhausting. However, that hurts higher rpm power due to limited exhaust "clean out" time.

Probably not the best way of explaining it, but that was approximately how an engine builder smarter than myself once explained it to me.

 

pm cutlassefi he'll tell you all you need to know

 

Nah that totally sounds legit. I've heard much the same.

 

then why are you here asking questions about it? go get your cam from delta... if they have been in business 50 years, they should know eh?

 

Just pays to get ur info from multiple sources. Delta has been on the scene a long time and now theyve even done impressive work with import guys too. They aren't exactly an olds SPECIALIST however.

 

The basics of dynamic compression aren't what I'm keen on contemplating here really though. I'm more interested in the build cylinder pressure for torque since you won't knock based on static compression school of thought vs the open it up and let scavenging do its thing, 3.42 is enough gear to lose dcr to overlap school of thought.

If the engine ends up lazy off idle but strong in the mid to 5500 RPM range I could live with it until I could crutch THAT with some stall... But historically the car was uber torquey and eager to roast em with the tiny stock cam that took a crap around 4k.

I've always been a smaller is better type guy, like I said I'm not tryna wring a stock motors neck. I've read about big cams killing good combos, and want to avoid that path obviously. Cam can wait for compression.

 

Cutlassefi quoted me the same price if not a bit cheaper then the off the shelf cam and lifters delivered to my door new ground to my engine specs just saying

 

Well I'll let him chime in here before I bug him unsolicited via pm. Besides. Posts w detailed geek speak are great for the community.

 

he won't mind you contacting him... he'll be more than glad to help you out...

 

Done, let's see what he has to discuss!!

 

X2 he has spent alot of time helping people out even if you don't buy his product

 

Happy to help. Stick with a single pattern cam, something in the 215-218 range at .050. You have a fairly restrictive intake side. The regular Performer has tiny runners and a 650 isn't overly large either. The spacer should help. Ask Delta to supply you with their advertised specs, at what tappet lift, as well as @.050 and @.200. That'll give you an idea of the aggressiveness of the cam. Thanks!

 

U have a hydraulic roller in a 350? *drools*

 

Will new cam selection throw off where I put my x-pipe enough that I should have its placement recalculated? The guy specd 68.5 inches behind the collector flange for my stock cam and built it so I could swap ends to change that length up to almost 75"

 

Not on your build. Especially since you didn't weld the center divider and fill the crossovers.

 

I'm weary on filling the crossover, but the center divider y speak of is on the center exhaust port right?

I've done searches but all I can find is that it changes the exhaust note. Would it be worth doing before we plop em in? The girl at the shop will do it up for me for less than 50$ a head including dissasembly

Also, is filling the crossover bad for a daily driver? Not that it ever gets that cold in Tacoma but I NEVER had a drivability glitch with the car as is. Will reducing heat up top expose my carb tuning weakness?

 

I have filled crossovers, runs slightly rougher in the cold and you need an electric choke. The area is very small on early heads, at least on mine anyways. I tried JB weld high temp expoxy on the divider, should see if it blew out

 

So at least the divider is a no brainer? How cold we talkin? It spends a lot of time around 40 degrees here nearly year round.

She'll do both of em for 10 bucks (divider only) if I disassemble the head (90 to do divider, crossover, and disassembly)

She won't weld unless its apart which seems legit.

 

You will notice it somewhat, but will only be slightly choppy. I would mill the #4 heads maybe .020" or get the .011" shim gaskets from Smitty at M&J Proformance. That will put you around 9 to 1, allowing a bigger cam. Add in low-mid 2000's stall and 3.42 or steeper gearing and 14's will be very achievable.

 

Would love to have gained compression w the heads but two things, first aren't they like 125 bucks? (The steel gaskets). And two, aren't they iffy if you haven't trued up the mating surfaces? I've heard different things regarding that.

Plus the gasket set comes w permatorque head gaskets, and thattl seal up regardless, and is zero additional expense.

Car is 3.42/posi th350 and 10bolt w stock stall as it sits.

We also have flat probe srp pistons, 224/234 cam, and plans for a 330 crank in the wind, so ultimate performance can kinda wait.

Seems like the exhaust divider should (and will) be improved.

 

Although now I'm reading that it isn't worth anything without filling the heat to the carb thing... And the same reading has revealed that below 45 and moist is no fun w no heat to the carb, so I think that it may be best to just wait. Work with the out coming 7 heads that will be done up fancy for the next iteration of the motor.

 

OK cutlassefi you say single pattern, what gives? Not the answer I'd traditionally have expected, yet your knowledge is very well respected.

So why would a single pattern be well suited? Down to learn something every day, especially about things as exciting as cam timing. (No, seriously.)

I was reviewing stock cam specs and had a thought I hadn't had before. If delta can grind anything, they can grind this.

Olds PN 387484 52deg ovrlp 278/282adv .430/.432 Desc 1964 330 Police Pursuit

 

Guess google doesn't always return only frustration!

http://www.442.com/oldsfaq/ofcam.htm

 

Or like maybe this.

402486 48 262/274 .440/.440 3269 AT, 350 Pol.

Works w auto from factory, .040 more lift, also same cam as 72 350 w std tranny? Idk if I knew they did that.

Anyway, compare it to my stocker

36deg ovl 250/264 .400/.400 350 L34, 350 AT

 

Simple, you have marginal compression and you've done more mods to the exhaust side than you have on the intake side.
More exhaust lobe will negatively effect low end and your intake, Performer, is tiny. A single pattern cam would work best for your current combination imo.

 

Word. Makes total sense. Sounds like a different intake option will be considered for the next build. Thank you for the input.

The maximum lift on stock valvetrain is near .5 right, so would the lift figures from a big factory cam be a good bet? .472 seems like it was widely used.

 

Should the cam grinder know what pushrods I need for the reduced base circle on the stock valvetrain? Or will measurement be needed....

 

You'll still need to measure. Yes .500 is about it.
If they're going to do your cam with old GM hi perf lobes (204, 214, 224@.050 etc) then have them do a 214/214 on a 110. That would be the best choice of that lobe series.

 

Wow, with near .5 and duration like that its gonna be a good deal hotter than stock!!

Might just have to bite it and get the steel gaskets if I gotta wait to afford pushrods anyway.

Is the idle on that at 8.5:1 gonna be pretty choppy? Not too concerned w lope but I don't mind a LITTLE on a dd w auto

 

I've never read about it, but have HEARD that in engines with low static cr sometimes a reverse split profile is used.

Given the work to the exhaust and the marginally better than stock induction, would this be an idea to consider?

 

I'm thinking 210-214 on 110 might be what I go with, .470+ or - lift. Will be talking w delta soon so I'd like to nail down our final thoughts here.

I feel like the mondello JM 18-20 we have is too big for my cr, and as discussed its split 216/226 duration would be less than ideal. Taming the exhaust duration will make the single pattern feel smaller or something right? 214 > 216 ...but not by much

 

First ive read about reverse splits from a Chevy forum:

"Our circle track engines we run mostly 106 lobe sep and we use high scavange exhaust systems and split pattern cams do not work with these exhaust systems.

Some of our 2 barrel engine we may run a reverse pattern cam on short track where more torque is needed."

This guy also explains how traditional split pattern cams do not work well with exhausts that have improved scavenging, and that a single pattern on a 110-112 lsa would feel "snappy" in an application like mine (but Chevy)

I'll totally shut up now.

But does any of this advice sound familiar? Thanks again for your input guys!!

 

And delta will use an oversize cam blank that works 100% w factory stock valvetrain. Cam will be ordered at once.