That motor from S-D was a 572 pumping out 620 hp.

[sm=icon_cheers.gif]

 

Thanks all for the replies. I'm currently leaning toward that 572 with the 9.6:1 compression ratio.
I'm assuming I'd need a new radiator as well, but other than that and headers, what else would I need?
And what kind of extras could be done to the motor for more HP/torque? I realize it is quite a bit as it is, but I do want to have the ability to gain more in the future if I wanted to.

As for stall converters and gear ratios on a TH400, what would be best, as well as where to buy one?


With 620hp, how fast would my baby be going? I don't know too much about cars lol.

 

For what it's worth, I have 11:1 compression and I've found that I can't run pump gas (93 octane). Sure it will run on it but it bucks and pings and if you retard it enough to stop the pinging its a poor running rough idling slug. I found that if I mix enough 110 octane fuel in to boost a tankful to 96 it never pings and has plenty of power and even idles decent. I suspect that you'd have some troubles with 10.5:1 as well.

Consider cutting back some of that horsepower for driveability. You may find that you're happier with a package that is a little less tempermental then something that has the horsepower maxed out. Also, don't forget about torque, horsepower is awesome over 70mph but torque rules at the stoplights. Keep weight in mind too, these puppies handle a lot better with a small block.

For an overall great package I like the newer LS motors. Fuel injected and lightweight for the power they're making.Plenty of high performance parts (like superchargers) available in the aftermarket. I'm not a huge fan of computers but they sure can tune an engine and save you gas as well. In short, if you want a good daily driver with plenty of power its worth looking at how the newer vettes are doing it.

Good luck with your search.
Rick.

 

Dj Envy: Like C3 said, don't bore if you don't have to as you don't pick up much displacement. A .030" over on a 350 gives you 355. You could check and see how big of a piston you could get which is probably .060" over.

DV8: A 383 is a 350 with a 400 crank.

Texas Jim: One thing I learned about CRs is there is calculated and effective. The effective takes in to account the cam overlap which reduces the true (calculated) CR.

 

rick,
For the 10.5:1 on pump gas, these are set-ups that I've read up on in a number of magazines. Considering that the magazines are alittle over confident in many cases, I imagine that with a really good set-up with all the right components, someone with a good amount of know-how and money could make it work. This is what I mean when I say it's "the limit."
shark,
Calculated or effective, with the pump gas of today, ratios that high are "pushing it." You're not the only guy who's read about or experimented w/ compression ratios in a life time.

 

I have a pumped up ZZ4350 fast burn crate engine putting out approx 435hp 9:6comp and runs on 93 octane. If I had any more HP it would not be fun to drive on the street. Even now I need to be very careful when I let the clutch out so I do hit the car in front of me. This does have something to do with the 4:10 posi rear and Comp High Energy Cam.

You really don't need more HP then what I am running, just the right gearing.
Cars handle much better with small blocks.

Total cost for the crate engine and upgrades $6600

 

shark,
In reference to your comment on "valve overlap" or "lobe separation angle;" I realized just now that you mentioned "valve overlap" lately in another topic also. The way you explain "valve overlap" you make it sound like any cam with any overlap will make an engine have a significantlylower amount of compression. I'm just saying that it seems like you're overstating "lobe separation." Indeed both valvesare open at the same time, but it's for a"super"small amount of time that this occurs. If overlap was as great a situation as you seem to state, then these hot sounding cams with a real rough idle (lower number degree of lobe separation) in a relative engine wouldcause aSUPER low amount of compression reguardless of the big domed pistons and small combustion chambers, or, how could you make big compression in a monster motor if this big cam is getting rid of all the compression?
Please don't take me as if I'm being ****ty, but this is the impression that I get when I read your replies.

 

When you measure BDC to TDC that is your "Static Compression Ratio",
when you take into account how far the piston has moved up before both valves close that it "Dynamic Compression Ratio" PG.

 

Maybe I'm confused but I thought lobe separation angle (LSA) was the angle between the intake and exhaust lobe's peaks. Valve overlap was the amount crank rotation when both valves are open. I think the purpose of overlap is to help scavenge the exhaust gases out and pull the intake charge in.

Anyway my L-82 cam has 52 degrees overlap at .008" lift. Never could find the specs at .050" lift which is pretty much a standard from what I've read. According to my calculations, which may not be correct if I'm misinterpreting what lobe separation is, my LSA is 131 degrees which seems like a lot by today's standards and I don't have a clue what effect LSA has on performance. BTW, the L-82 cam is the same cam as the 350/350 cam.

Anyway when the engine is idling, it's pretty smooth but no matter how lean I make it, the exhaust is still rich (runs ya out of the garage). I attribute that to the AIR system being in the basement and therefore the extra gas in the exhaust isn't getting the extra air from the AIR pump to complete the combustion process. Thought about putting it back on but then I'd have to redo several pulleys since I'm using the old AIR pump pulley to run the A/C compressor.

Bottom line: If you see something I put on the forum that's incorrect, I don't take offense if you correct me. I'm just a self-taught shadetree mech.

 

shark,
You're right in your definitions.Lobe Separation Angle is the angle between the centerlines of the intake and exhaust lobes measured in "crankshaft degrees,"or (Overlap) the amount of time, in crankshaft degrees, that the intake and exhaust valves are open at the same time. So Lobe Separation Angle more accurately describes Overlap.
I have no problem with your terminology. I only feel that you seem to over-estimate the effects of Overlap.
And shark, thanks for being a gentleman about my comments. I meantthem in a discussion-type way, and I thought that there was a chance that you'd "come back nasty" after reading the reply. I've said before that I'd never be straight out ****tywith anyone on here and I haven't thus far, even though I may sound like a jerk sometimes, I'm not trying to be.
Just adding to your mentioning one of the reasons for "overlap," I read way back somewhere, possibly in a motorcycleengine article,that the overlap also allows a small part of the cool intake mixture to passout ofthe exhaust port to help cool the exhaust valve and seat.
*** Justa thought brought to mind by this topic; For performance purposes wego in the direction of making an engine as efficient as possible, and then for more performance we actuallygo in the other direction where an engine becomes less and less efficient, ie; alot of valve overlap. The inefficient burning of fuel/blowing raw fuel out the exhaust is the reason why the EPA cracked down so hard on 2 stroke engines, as they're very inefficient but run like crazy, andWITHOUT valves.I built an all-out 500cc 3 cylinder two stroke Kawasaki in '81. It sounded fantastic w/ the expansion chambers (w/stingers) and ran the same way. And the smell of raw fuel from the exhaustwas unmistakeably a super-runnin' two stroke. LOL