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| 170 or 225? https://slantsix.org/forum/viewtopic.php?t=59797 |
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| Author: | Charrlie_S [ Tue Jun 21, 2016 4:05 am ] |
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Quote: This also complicates things for years of engines from what i'm reading. after 67 the torque converter changes so if i use a 225 i need the older one.
Not really. All you need to use the late engine is an adapter bushing in the end of the crank, and the later flexplate. I sell the bushing, as do several others.
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| Author: | Joshie225 [ Tue Jun 21, 2016 7:58 am ] |
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If you really do want high RPM I'd find a block with good thick cylinder walls, bore it to 3.5" and use a 198 crank (3.64" stroke) and rods. If you do this with a short deck 170 then headers will be a Royal Pain, but it saves weight. If you use a 198/225 block then headers are easier by far, but there is a weight penalty. Do the best head work you can or have Mike Jeffries build you a head and you'll be able to spin it pretty high. |
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| Author: | thegreengoblin [ Tue Jun 21, 2016 11:52 am ] |
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I did read some some stuff about making a stroker 170. sounds like it works but it's a bit of work. That would be pretty cool. none of the 198's had forged cranks right? Just wondering how much power a forged slant crank vs a cast slant crank can take? |
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| Author: | thegreengoblin [ Tue Jun 21, 2016 11:53 am ] |
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Quote: Not really. All you need to use the late engine is an adapter bushing in the end of the crank, and the later flexplate. I sell the bushing, as do several others.
oh excellent, then that's not too bad then
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| Author: | Joshie225 [ Tue Jun 21, 2016 12:29 pm ] |
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Every slant before mid 1976 has a forged crank. 300 hp cast crank engines have been built and lived fine. 200 hp engines have had their forged crank break. |
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| Author: | Charrlie_S [ Tue Jun 21, 2016 1:32 pm ] |
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I never could see the logic of building a 170 block with a 198 crank. It is still the same cubes as a 198 engine, if they are both bored the same. And the 170 block would require much more machine work. Both engines would be the same bore, same stroke, same RPM capability. PS: All 198 cranks were forged, as were 170's. Only the 225 had the cast crank, in the later years (after 1976) |
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| Author: | SlantSteve [ Tue Jun 21, 2016 3:16 pm ] |
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Quote: I never could see the logic of building a 170 block with a 198 crank. It is still the same cubes as a 198 engine, if they are both bored the same. And the 170 block would require much more machine work. Both engines would be the same bore, same stroke, same RPM capability.
More work,but definite advantages. Lighter overall weight,lighter recip weight due shorter rods and more compact piston design,reduced Piston speed better for high rpm work due shorter rod ratio.... Is it worth it?? We all have different objectives, I guess you have an engine that feels like a 225 in power output but spins better....the OP has already balked at the extra work involved so I'd say no in this case...but if I had a 170 I'd do it...sounds a fun build.PS: All 198 cranks were forged, as were 170's. Only the 225 had the cast crank, in the later years (after 1976) With a stroker 170 you still need enough cam and port to support high rpm...now that would be the hard part on a slant,it would need a lot of good port work.Personally I see no point of wanting to spin and engine for the sake of it if it's waaaaay beyond its power band,I think the OP should just build a stock 225 for a streeter. Spinning a stock slant to 6000?? Really what's the point? your probably making less power than the thing makes at 3000 and it will go boom one day,I guess a 170 may tolerate it for a bit longer....If you want to see 6000 on the tach set it to 4 cyl so it over reads |
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| Author: | thegreengoblin [ Wed Jun 22, 2016 10:17 am ] |
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Quote: Every slant before mid 1976 has a forged crank. 300 hp cast crank engines have been built and lived fine. 200 hp engines have had their forged crank break.
Ok then I wont worry about forged or not.
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| Author: | thegreengoblin [ Wed Jun 22, 2016 10:21 am ] |
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Well, sounds like everyone uses the 225 for making power. Seems logical enough. I'll see if I can find a 198, but might just be easier to grab a 225. So with intake, headers, bigger carb, cam and some head work 200 whp? |
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| Author: | Joshie225 [ Wed Jun 22, 2016 10:37 am ] |
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With an expertly prepared cylinder head, enough cam lift and duration and enough compression, yes. The head work will make or break this. |
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| Author: | dodgedartgt [ Mon Jul 18, 2016 8:06 am ] |
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Quote: This also complicates things for years of engines from what i'm reading. after 67 the torque converter changes so if i use a 225 i need the older one.
Not true...I don't believe '67 was the year, I thought it was '65(?)..... Anyhow, the registration snout on the earlier torque convertors was smaller in diameter than the later units, ie, where they fit into the crank. Ed Yost at Wildcat Auto Wrecking in Sandy, OR (503) 668-7786, sells an a machined adapter ring for $20 that mates an earlier trans to a later engine. Piece of cake! BTW, the earlier trans has the pump in the rear, as opposed to up front. Because of this, you can actually push (or pull) start the earlier cars with the push button auto transmission. Mike in FL (formerly OR) |
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| Author: | Joshie225 [ Mon Jul 18, 2016 8:37 am ] |
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1967 was the last year of the small pilot hole crank. 1965 was the last year for the rear transmission pump. The adapter bushing works fine for using the 1968 and later engine with an earlier automatic transmission. |
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| Author: | JohnnyDees [ Thu Sep 22, 2016 6:35 pm ] |
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so can you use the later convertor with the early trans in a later engine? |
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| Author: | Charrlie_S [ Thu Sep 22, 2016 7:21 pm ] |
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Quote: so can you use the later convertor with the early trans in a later engine?
Not unless you install the later front pump, clutch drum and input shaft into the eary trans. But you cannot install the late low 1st gear parts in the early trans. It is easier to just use the adapter bushing in the late engine, and the early trans and converter.
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| Author: | JohnnyDees [ Thu Sep 22, 2016 7:39 pm ] |
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Thanks! |
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