Hello all, it's been a while. Way back in 2023 or so i posted about a piecemeal slant six NA build for a prospective car; in late August, I picked up a pile of a '74 Scamp with most of the parts needed for an 833OD swap. My problem is that I originally wanted only 180hp or so out of the 225, and was assured that was completely doable NA and it would be fairly drivable. My goals have now raised to 250hp, and I'm not entirely sure that's reasonable without going to boost. I've already got the rod/piston set for 10:1 comp ready to go into a forged crank motor, but I've also just picked up a good cast crank super six that only needs a reseal and would likely be a better candidate for a build given that it's a much later engine and the crank weighs slightly less than the entirety of Lubbock, TX. Need thoughts here.

250 HP is doable, but challenging. You will need a very good cylinder head porting job w/big valves, and every other part very carefully matched and assembled. Better questions are: (1) How much can you spend on this engine and the rest of the drivetrain? (2) How fast do you want the car to be? (3) What experience as a mechanic do you have?

Let's have a discussion...
Lou

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Home of Slant6-powered fun machines since 1988

I like the slant. I like the idea of high power slants. But if you want 250 NA HP with reliable and daily drivable you are much better off going small block. It will be much cheaper and easier to source parts. The head is a large roadblock to NA power, forced induction overcomes some of its shortcomings.

My own personal goal is 200 hp from a boosted engine for the same use case (reliable driver).

With the light weight of the a bodies from the era you don't need a lot of power. Modern cars have more weight with similar power ratings to your goal and way less torque. They offset the lack of torque with much better gearing and number of gears.

I'm planning on a light rebuild of whichever engine I'm not going to use just so I can have the car running and driving while I build the good one, so cost isn't necessarily a huge issue (but obviously I dont expect to get this thing done overnight). I'd like to keep the slant for now as a SB bellhousing is going to add hundreds of dollars and I've already got two for the slant. Small blocks are neat and all but my other two vehicles are already V8 powered and it's time for a straight six again.

I've got a fair amount of home mechanic experience and a degree in auto tech which looks real nice on a wall but so far hasn't done me a lot professionally.

I guess I could drop it back down to 200hp NA. I know other stuff is more powerful and I know the car is lighter than my other stuff; 180hp would get me right in the same power to weight ratio as my daily.

I've already got a good rebuilt head with 340 springs and (supposedly) some port work to remove the excess casting behind the valves, so that'll likely go on whatever engine I put in the car as a placeholder. I'd like this car to be fast enough to be fun - it's getting aallll the handling upgrades (torque boxes, sway bars, chassis stiffeners, etc) so enough power to use that handling would be nice.

OK, this looks like a more reasonable approach/outlook. 200 HP NA is not too hard, but you still will need some head porting. I find that HP level plenty fun. Try to find some 1.70/1.44 valves and get those put into the head and do some pocket porting when you do that. Shoot for 9 or 9.5:1 compression and use something like the Oregon 346 cam degreed at 100 deg intake centerline. Offy 4bbl intake with Holley 500 2bbl or Edelbrock 500 4 bbl. Recurve distributor. Clifford shorty headers or Dutra Duals with 2 X 2" pipes into a 2.5" single out the back, with the Y-pipe just behind the trans X-member. I can go on...

Old A-bodies are lighter than new cars of similar size, although 74 started to get heavy. 3.23 or 3.55 gears for street use. If using OD 833 then use 3.73 or 3.91.

Lou

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Home of Slant6-powered fun machines since 1988

Here is a good build thread to mimic to get what you are after.

Maybe start at page 21 - that's were I get into the Engine Build.

Here are the results of the car when I have not broken it.

Here is a good comparison from Mild to semi- Wild Slant 6's


Best of luck!

Greg

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http://www.youtube.com/hyperpack

Good stuff, thanks guys.
Probably unpopular, but I'm gonna try using a Qjet. I've got like five extras, all the parts to rebuild them, and I've gotten decent at tuning them. Going for Dutra Duals for the exhaust as I eventually want to run triple Webers on this and DDs are required for that (mostly for the cool factor), but that setup costs nearly three times as much as I paid for the car.

While we're here, anyone have a suggestion for an off-the-shelf cam for the very mild build I'll be slapping in while I build the nice engine? Basically just re-seal/minor porting/springs/2bbl. I was looking at the Hughes Whiplash.

I like the looks of the Howards Cams 214/214, 0.450" Slant 6 cam. Summit has them but I can't find it right now. I have one on the shelf but have not run it yet. The "RDP10" cam from Oregon cams (need to send them a core) also work very well for mild motors.

If you have the knowledge and the parts, then trying a Qjet sounds good to me. A few people have tried them on this board, but I do not recall results. The small primaries should work very well.

Lou

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Home of Slant6-powered fun machines since 1988

I just talked to Ken at Oregon Cams and he gave me a new grind that was not in any of our cam lists. It would be decent for what you are doing I think. It is 212 @ .50 with @ 440 lift on a 110 ICL. I got this for my truck for the engine that burnt a piston at Knoxville last year.

PS. He is supposed to send me the latest cam list with my cam.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Cool stuff thanks rick.

Post up the new info when you get it.

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http://www.youtube.com/hyperpack

As said before, the keys will be good headwork, and getting a little more compression in it. Fairly mild cam with the Dutra manifolds and you probably will be close to your 200HP mark, but more importantly it will make lots of torque, and that's what you need on the street.

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Official Cookie and Mater Tormentor.

I'll make a call to Oregon Cams sometime this week - I don't currently have a core cam (curse ~5yrs ago me for not knowing rusty old stock cams were valuable) but I can rip the one out of the super six if need be. Channeling my inner Columbo with "just one more thing," but I was wondering if anyone here knew of a good machine shop for head work around the PNW. I'm not yet sure if I want to try the porting myself, so if it's reasonably priced I may send it out for someone actually qualified to do it and have the big valves put in at the same time.

Unfortunately had to take some extra time off this week to deal with... this... (starter) so I'm not gonna get to buy stuff I wanted to buy for the Scamp.

If someone on here does not recommend a head porter, I bet Ken at Oregon Cams would know someone.

Lou

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Home of Slant6-powered fun machines since 1988

That isn't actually a bad spot for a starter that lasts 200K+ miles.

Is that a toyota 4.7L? If that is a toytoa denso unit you might even be able to just replace the contacts. They were a common item 10 years ago and cost about $15. Way cheaper, easy to do, and the starter retains factory reliability compared to parts stores wishful thinking units.

1UZ-FE, 4L. And yeah, I didn't even replace them or remove the starter - cleaned the solenoid plunger up in a drill, used the same drill and a wire cup to get the contacts inside without taking them out. Works fine now, but doing it the first time is unnerving. Plus, I work slow.

I'll ask Ken when I call Oregon Cams if he knows anyone who'd be willing to do port work. I was hoping for someone close to me, but I realize that's wishful thinking anymore.