Hello guys, I'm looking to improve my Olds performance a little more, car has the original smog 1974 455, TH400, 3.23 posi gears, long tube headers to a 2.5inch exhaust. What is the next upgrade(s) I should go for? Can i go for a mild cam upgrade or not? I'm ordering all parts together so I can ship them in bulk and not have to sell a kidney to pay shipping and customs.

 

I'd suggest reaching out to CutlassEFI (Mark Remmel) on this board - he's a known BBO building expert on this site and can guide you on specific part upgrades if not otherwise an entire (re)build - can also likely sell you whatever new parts you ultimately decide to purchase.

 

Mill the heads, use a thin head gasket, try to get a little compression in it. Definitely get rid of the lazy stock cam and timing set.

 

Agreed !

Andrew you've covered the basics save for maybe a more aggressive torque converter. But I doubt that will satisfy your wants. I see the headers you just added didn't have the impact hoped for... ? It's the weight. A 74 455 numbers matching 442 is way cool. But they are also the heaviest 442s in history. And yours as I understand it has every option available. So likely 4500 lbs with you in it. 300 hp and 400 lb ft gross won't cut it in the nimble department.

Built with 70sgeek and Matt69Olds suggestions makes the most sense. You've come to that crossroads. I would think 400 hp and 500 lb ft should do the trick. Then again if you are going that route maybe don't hold back...

Imagine if Olds never had to hold back post 1970. Imagine if the rules and regulations that kicked in never happened. Maybe your car would of been born with 450 hp. In a sense you'd be creating what should have been.

 

Whats your budget ? That low compression ratio diminishes increases of most tuning and parts changes.

 

whats a “little more” mean? if it’s still got the original smog Qjet, replacing it with a good aftermarket carb would give you more than a little more.

have you had it to the track to get some numbers that you want to improve on?

 

Budget?

 

nope

 

Not looking for a crazy racing build, I'll probably repalce the J heads with some older model ones. I've been eying a flat tappet comp cam kit for a while, 224/230 part #K-42-223-4, 110 lobe separation, 224/230 @ .0.50. is this a good choice cam? do i need to change the torque converter or can I keep stock one?

 

I’d do the cam below that, 218/224@.050.
And unless you’re going to cut those heads significantly, changing to earlier heads won’t help you much in the compression dept. By the time you add the thicker head gasket vs stock, you might even have less compression than before,

 

I'll look into the cam you recommended, I don't know how much the heads would help but that would be for another day to think about. I think the cam kit upgrade will probably be the next upgrade for now.
What is the stall spee on the stock th400 torque converter?

 

At the minimum, you need to mill the heads an equivalent amount of the added thickness of the replacement head gasket. Ideally, you need to mill the head and run a thinner gasket. Of course, then you run into the issue of intake bolts lining up and measuring for pushrods.

 

Interesting !

Andrew if you haven't gone to the track, how is the seat of the pants feel/butt dyno, does she wheel spin when you punch it ? Is it chirpy ?

As I understand it coupled to a 455 it stalls around 1600... its low.

When I was going to the track regularly with the 69, seasoned track guys told me the stall was holding me back. For my TH350 and 350 CID she flash stalls at 1400, very low. Especially because I don't rev her on launch I just gun it. Something along the lines of a D5 converter is what you want. It makes a big difference on the lowly 307 H/O. It will be awesome with your 455 stock or mild. 2200 give or take depending on combo.

With CutlassEFIs cam recomendation 218/224@.050. the power band starts at 1600 rpm so 2000 or so stall works.

Stock your 455 is producing 275 lb ft at 1600 rpm, but its producing 325 lb ft at 2000 rpm and your stock peak torque is 370 lb ft at 2800 rpm. (net)

You see how much harder you will come charging out the gate.

My 69s 350 is producing 215 lb ft at 1400 rpm, but its producing 300 lb ft at 2000 rpm and my stock peak torque is 390 lb ft at 3200 rpm. (gross)

In other words my stock stall is devastating to performance but she was not a performance car. And she will be a different animal with a 2000 rpm flash stall. On the street she already wheelspins when punched so that will get worse with a more aggressive stall as well.

You seem to be the patient type. Maybe try CANADIANOLDS better carb and the better stall and then the next step is the more aggressive cam. I think both will help with or without the cam anyway, so you cant go wrong. And the cam should put you over the top if you still want more.

The famous Hot Rod Magazine article "Junker to Thumper" from June 2003 is your friend. Where they took a lowly but still healthy smogger Pontiac 455 straight from the junkyard. Freshened it up, put on engine dyno and saw 243 hp. Then added an intake, cam, and headers and saw 350 hp.... Apples and oranges comparison but close enough...

 

The carb is from a 1793 350 based on stamping number, would a recalibration kit bro qjet power be enough to improve it or is it better to replace it with something else? A slightly higher stall converter seems like a good idea. I’m gonna have a look at that article too,

 

The problem with any factory Qjet is the idle circuits from the smog era. Hopefully guys who know the mid 70's 4M Qjets can speak on how lean this carb is. Yes you can change rods and jets on the primary and rods on the secondaries but idle passages need enlarged when a larger cam is used. Also need to check the secondary air door opening. Your carb is also only a 750 cfm, not 800 cfm like later carbs. My understanding is they are rated differently than other aftermarket carbs for CFM. If you going to mess with a Qjet, get Cliff's book, his high performance kit and a 76 and later 800 cfm core. I bought a 1983 800 cfm Canadian export 307 carb that was so lean it would not idle properly on a stock 73 Olds 350 with headers. I built it with parts including idle tubes from Cliff with his book and talking with him on the phone for a planned 450 HP Olds 403 build with an aggressive cam. Changed my mind, I like a smooth idle and sold it to a member who built and dynoed a 450 HP 403 but wanted a Qjet. He said it worked quite well. It took many hours, rebuild including throttle bushings plus Cliff's tricks I did, made it a 850 cfm instead of a 600 cfm, the secondary air door barely opened and all his high quality parts including a slower release pull off. It can be done but some Qjets require extensive modifications. The higher stall alone will help a bunch. If you are changing the cam, get a Performer intake, way easier to put back in and makes a square bore carb swap easy. Good luck.