Call / pm Doug Dutra.
I think he built that combo in the 90's / early 2000's
I mean he did write the book on this sorta thing
Greg
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| Talk to me about this 170 Block, 198 Crank Deal https://www.slantsix.org/forum/viewtopic.php?t=64103 |
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| Author: | hyper_pak [ Sun Sep 29, 2019 4:46 pm ] |
| Post subject: | Talk to me about this 170 Block, 198 Crank Deal |
So I have this drag car and I am thinking about my options. This stroked 170 has me thinking. I don't have a 198 crank, small problem, I do have a 66 170 engine, good, so someone talk with me about this plan! Thanks in advance. Here is the tech article: A STROKER 170 You don't think a 4.15" long-stroke engine is where it's at? You want a fast-revving, lightweight engine? How about a 210 CID low-block 170? I built one of these for my '68 Hyper-pak equipped Barracuda drag car. This was done using a 198 crankshaft in the 170 block with a 0.100" overbore (3.50" bore). I used Chevrolet Vega 144 CID pistons on 170 connecting rods, which gave 9.2:1 compression. Sounds easy? It's not, because the longer-stroke 198 crank does not quite clear the 170 block's crank pocket. To make it fit, I ground metal off the crankshaft counterweights and a small amount of metal off the bottom of the block's cylinder bore area. Most of the crank clearance grinding work was done on the first and last small crankshaft counterweights. Approximately 0.300" had to be trimmed off these counterweights so they would clear the bottoms of #1 and #6 pistons, solving the interference between the crank counterweights and the bottom of the piston's pin boss area. In order to rebalance the crankshaft after the modification, some weight-reduction holes had to be drilled into the large center weight in the middle of the crank, 180 degrees opposite the work done on the end counterweights. After this, everything cleared and was rebalanced with no added heavy (and expensive) Mallory Metal. This engine runs well and is 50 lbs lighter than a 225! It's proved a strong engine with no problems in five seasons of 7,000-RPM-redline drag racing. If I were to guess at a weak spot in this engine, it would be those Vega pistons, but so far they've held up. |
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| Author: | Greg Ondayko [ Sun Sep 29, 2019 6:25 pm ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Call / pm Doug Dutra. I think he built that combo in the 90's / early 2000's I mean he did write the book on this sorta thing Greg |
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| Author: | Rick Covalt [ Mon Sep 30, 2019 3:17 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Stan, for Drag racing the only question for me would be this. Is giving up nearly 30 cubic inches (210 vs 238) made up by turning 500 more RPM? This 210 is more work, to lose cubic inches, when the object is to go fast. At 1 HP/ cubic in. your giving up 30 HP. It was a cool build and Ryan actually wants to do one some time too, but I am not sure it is worth it. Loosing 50 pounds would be nice though!
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| Author: | hyper_pak [ Mon Sep 30, 2019 7:39 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
I hear you. However I am not sure about the RPM numbers. I know the 170 motors can run some very high RPM. It's something I think I want to try and see really what it will do in my car. I am thinking I will be around 2200 lbs. and after I run my 232, I will swap motors. Just thinking out loud. Thanks for the input. |
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| Author: | GregCon [ Mon Sep 30, 2019 10:37 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
The 170 deserves far more respect than it gets....after all, it is the Slant Six in its most unadulterated and original state. If it were a movie, it would be Rocky - before all the sequels. If it were an Olympic star, it would be Bruce Jenner...not Caitlyn Jenner. |
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| Author: | Greg Ondayko [ Mon Sep 30, 2019 11:44 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Its easier to loose 50 # in other spots... but if some of that mass is spinning things containing rotational inertia then it starts to become more viable. Greg |
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| Author: | Dart270 [ Mon Sep 30, 2019 3:13 pm ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
I think it is more like 25-30 lbs weight loss, according to all my measurements (many blocks and cranks of all years/types). I also want to try this, and have a 170 block and 198 crank mostly prepped. Time is the missing piece... Lou |
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| Author: | hyper_pak [ Mon Sep 30, 2019 5:29 pm ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Ok, so I need a 198 crank, Anyone? Bueller? Bueller? Bueller? |
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| Author: | hyper_pak [ Mon Sep 30, 2019 5:30 pm ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
And I am not worried about the 50 lbs., I will have to add weight to make the min. |
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| Author: | Rick Covalt [ Tue Oct 01, 2019 9:02 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Quote: I will have to add weight to make the min.
What Minimum is that Stan?
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| Author: | hyper_pak [ Tue Oct 01, 2019 10:52 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
The A class, 2000-2349 Lbs. Maybe I said that wrong. I am building to run in that class. |
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| Author: | Rob Simmons [ Tue Oct 01, 2019 11:51 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
And if you run for a record at that weight running a 170 you actually fall into B Class for the official record. It's a little bump Seymour gave the underdog 170 many years ago. 
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| Author: | Rob Simmons [ Tue Oct 01, 2019 11:56 am ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Quote: Ok, so I need a 198 crank, Anyone? Bueller? Bueller? Bueller?
I don't know if I have one or not, but will look as I move all my junk into the new shop.The forging number on the 198 cranks are 2951979 or 2954265 according to the table in the articles section. It is located between #3 and #4 rod journals. I wanna build one too! 
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| Author: | drgonzo [ Tue Oct 01, 2019 12:11 pm ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
Hmmm, so records are based on the block used regardless of displacement? Not that I am about to set any records, but... inquiring minds, you know. |
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| Author: | Rob Simmons [ Tue Oct 01, 2019 12:33 pm ] |
| Post subject: | Re: Talk to me about this 170 Block, 198 Crank Deal |
198 and 225 are the same. It is only the 170 that gets the extra weight advantage. To date I believe only Charlie Schmid has taken advantage of it. On his latest record we added (170) next to the vehicle type to show that. http://www.slantsix.org/forum/viewtopic.php?f=2&t=64058 Quote: Of course all entries must be powered by a Mopar Slant 6 engine. For purposes of these records, this means that the engine must be based on a Slant 6 block. The head may be modified in any way, replaced by one from another engine, or may be entirely fabricated. The above classes are based on the high deck 225 block, if a low deck 170 type block is used, the car will be moved to the next heavier class. That is a car weighing from 2,350 to 2,699# powered by a 170 type block would be classified in the “C” class.
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