Hi, I'm new to this place and looking for some advice. I've got an '81 D150 shortbox, stepside I'm trying to choose a cam and intake for. I've owned a bunch of /6s over the years but usually just ran them into the ground if they were 4 doors or yanked them out to put 340s/440s like a '74 Duster and a sackful of '68 Hardtop Darts. I've got the big inch itch covered now w a '66 Belvedere w a 440 and just want to build a strong, dependable 225 for this truck and then build a snotty slant after that for a jalopy hotrod I've been piling parts up for for a decade.

OK, here's what I have so far,

Engine, 1981 225, old long tube Clifford headers, Chrysler electronic ign. a new Holley 2 bbl Sniper EFI in the box, '74 head -090 w hardened seats, basic Edelbrock Smallblock springs, a portmatch and basic bowl cleanup and streamlining. Not planning on big valves but I backcut the stock valves and rolled the back edge of the exhausts. I like solid lifters.

Truck is OD A833 with a 3:55 8 1/4" w a Powertrax drop-in locker. I lowered it 4ish inches in front w Van Lower Control Arms and not quite that much in the rear w drop shackles. I'll build a set of home made Caltrac bars to help it hook if it needs it but only have 15x8s and hard as rocks Michelin truck tires.

It's a driver that I want to be able to spin the tires and make a little trouble with but still drive it home to Texas when I need some Brisket. I'll probably take it down the strip once in a while but I'm not emotionally invested in what that number turns out to be.

I've been around a bunch of hot Slants way back in High School(Carter administration)but it was all Offenhauser 4bbls and Purple Shaft cams back then so I suspect I'm about to screw this up if I don't ask some questions. Is this a good candidate for one of the Reverse Dual Pattern grinds or something like that and what would a good manifold choice be? I've got an old Offy 4bbl that won't play well with the EFI and various factory manifolds like an aluminum 2bbl I could put an adapter on for the larger Holley pattern but I see all those tasty bits over on Aussiespeed's site. Does anyone have enough akshul nolige to pick between their Long and Short runner 2bbl options? I'm not expecting miracles but I'm not going to throw any stray HP away either. I'm doing fresh air to the throttle body, electric fan, home made deep pan with a windage tray etc. etc. I'd like to know a little more about intake manifolds before I call Oregon Cam Grinding and do something crazy.

Anyway, I'm excited to finally do something with all this Slant Six stuff that's piled up among all the 360s and 383s and 440s. What do you think?

Spindizzy

Welcome!

The Offy intake will play fine with the EFI. It isn't a power gain over a well adapted stock intake, but the adaptation may be easier. The long Aussiespeed manifold would build some mid-range torque, but it's not a budget piece. The Oregon 819/818 lobes on intake and exhaust work well for a heavy vehicle. With the wide ratio transmission you need a broad torque curve. It won't be a tire burner, but it will drive much better than stock so long as the compression ratio is 8.5-9:1 and the timing curve is good.

I would reconsider using stock valves. You're leaving a lot on the table that cannot be made up for with an expensive intake manifold. I've done the small valve, long cam thing and it was worse overall than big valves and a stock cam.

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Joshua

Josh has some nice thoughts there. Agreed on the larger valves vs. obsessing about intake and cam. Offy will actually do very well unless you are trying to make max power above 4500-5000 RPM. Clifford 4bbl is the best for higher RPM HP - better than the Aussiespeeds. The Aussie long runner is the best low-midrange intake I have yet run, but really runs out above 5000.

I take it you like a bumpy cam? 0.090" off the head assuming everything else is bone stock will get you in the neighborhood of 9:1. You could run up to an Oregon 346 cam, degreed at 100 centreline, but you could be happy with a smaller cam too.

Where are you located?

Lou

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