I need to build a new motor thinking 598 CID area def want to run alky would ya stay conventional heads or go to something else? single carb deal and probably some .90 stuff
Posts: 418 | Location: Bellingham MA | Registered: October 21, 2004
Alcohol would be best on a conventional head although I'm pretty sure Oakley has some SR20 alcohol stuff out there now. Baby blowers (TBS 250) are all the rage right now you could probably out run the 598 combo with a low boost 565.
In general terms, why is that? I've never dealt with alcohol but it seems with using almost twice the amount of fuel in a wet flow manifold, with less than optimum runner design, would produce worse fuel distribution and thus power.
Illegitimi non carborundum
Posts: 2385 | Location: OKC, OK | Registered: February 15, 2008
Originally posted February 24, 2020 07:46 PM by camaro77: looking for a low maintaince motor bracket racing and some .90 stuff 1000 hp 565-615 not really set in stone car is a tube chassis car currently have a conventional head DART 320's that are 20 yrs old I hear a lot of good things about the -20 heads. do I stay with conventional or switch to something else? things I know I want for sure are
big lifter bore belt drive shaft rockers steel rods for sure
If so a 582 on gas with conventional heads will easily get you over 1000HP built by any of the nationally known professional sportsman engine builders. 20 degree heads will get you about another 75HP. A 615 with 20 degree heads will make over 1200HP.
Originally posted by camaro77: Ed i def dont want a motor I need to tear down every few months.
all the above engines regardless of which nationally known professional sportsman engine builder builds it, should go hundreds of passes before needing a rebuild with nothing more than oil changes, checking the lash regularly and new valve springs at around 200 passes.
Posts: 13522 | Location: NJ | Registered: August 20, 2000
Originally posted by camaro77: I need to build a new motor thinking 598 CID area def want to run alky would ya stay conventional heads or go to something else? single carb deal and probably some .90 stuff
You looking at carb or injection for alky? With the carb, you probably want to look at the Brodix 380 or HH 383 heads at 598 set up. We have used the 383HH on a 598 with alky carb and the current set up is 615 with the 383HH with alky carb. All have performed very well. I have seen some pretty impressive 18* set ups using alky injection.
Posts: 2399 | Location: Ohio | Registered: April 01, 2007
Oakley has done some good going .90 with a blower. If it was me, I would call him, and talk about building a conservative blower set up. It would get you convenience of conventional heads, the alky you want to run, and et on a budget.
Camaro77, I agree with 1320 racer on the 582. Even a 572 4.250 stroke 4.625 bore will get you about 1000hp. and with out having to tear it apart all the time. Depending how much you race 200- 300 runs a year I would just go with what 1320 racer said check valve lash and rotate a set of rollers in at 250 runs,send first set back for rebuild,and rotate in the next year.With the oils today and the bearing material,and valve springs are the best we have ever had. All that being said in my own ,for what its worth,keep max rpm under 7800. Big engines running 8000 to 9500 rpm may and do require more care. Through the 1990 to around 2002 my 4.25 stroke motors I was reluctant to turn past 7200.Since then have moved the max up to 7800 although in 1/8 mile never gets close. And I also build my own motors so I see them going togeather and I seem them when I take them apart. I have run alky since 1992 both carbs and injection. I also have no problem with running gas either.
Posts: 321 | Location: ohio | Registered: June 06, 2006
Originally posted by camaro77: I need to build a new motor thinking 598 CID area def want to run alky would ya stay conventional heads or go to something else? single carb deal and probably some .90 stuff
What do you want to do,,, or how much power do you want to make?
Large CID motors 600CID and up will run faster with gas than alky, especially once you get above 1.8 HP/CID (1.8 x 600 = 1080 HP).
No reason not to run anything but a cast intake and a single carb!
About ten years ago I built a 565 with Brodix HH heads, their intake which is not the best, .799/.750" lift roller cam that made 1025 HP and there is no reason you couldn't go 400 runs with this combo with good parts and bushed Isky lifters other than regular valve lash checks and change the oil! I'd also check the springs a few times a year as normal maintenance. Unless you get a bad set of springs, they will last 400 runs.
As for cubes, I'd say 565/582 in a short deck or 615/632 tall deck. I see no reason to build a 598 unless you have parts already.
Gas (X16) to Alky carb makes zero difference on my 632. BB3 heads. The only difference is the fuel bill is more expensive on X16, even with having to warm it up more on alky!
Posts: 102 | Location: Ohio | Registered: December 19, 2014
Originally posted by 1320racer: Al, agree on all points and that 565 was healthy, what HH head did you use on it?
ED, back then I don't think the 395 MC head was available, even if it was I used the 383 HH heads, got them from Tracy at Sunset. At that time my car was 1925lbs and it ran 7.25 @ 185+ best, normal summer conditions low to mid 7.30's. And that was on Hoosiers too! Imagine how fast it would have been on MT's!
I also ran a Ron's Terminator on this combo. I did work with APD/John with a gas carb combo, it was slower with the gas carb, gonna say somewhere between .05 to .08 in the 1/4, that's regular alky to regular race gas. Gas carbs have since been improved a good deal so the difference is likely less now. I do feel that the Brodix intake was not the best for this combo but it was the only one that fit the heads at that time.
Originally posted by gxp7903: Gas (X16) to Alky carb makes zero difference on my 632. BB3 heads. The only difference is the fuel bill is more expensive on X16, even with having to warm it up more on alky!
Not saying I don't believe you but without specific details I will say you have a choke point below the threshold of gas to alky fuels. With those cubes, the heads aren't big enough on alky so something else is the choke.
