Just speaking to an old engine builder over here in Australia,weren't really on the subject of big bores but he mentioned using Holden 173 ci pistons in slants,these pistons are readily available in the Endurotec cast piston brand ,3.5" std diameter,comp ht 1.803" and a 22 mm pin diameter,so you have to hone them out to the Mopar pin size or sleeve the rod. It sounds like a far cheaper option to a big bore than the wiseco long rod setup,maybe for a hot streeter this could be an option? If anyone wants any further info I will ask him when I see him next time

sure, post additional info on the pistons,,I am guessing these would take the thin metric rings,, cost for a set of six (exchange rate) and shipping estimates would be good to know.

I'd be interested in this as well.

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65 Dart station wagon slant 6 - now under construction
47 Dodge Custom 4 Door sedan
87 D100 Short Bed slant 6

Retired USAF 1966-1986
Retired US Postal Service 2004-2014

Sure,will ask him when he's back at work in the new year. If you look on the Australian EBay site there are a set for about $180 Aus,that's around $160 ish in USD. As far as freight goes,doesn't someone here import stuff from Australia? The Aussiespeed stuff? Perhaps they could include the pistons in a shipment?

regards,Rod

If you would like another (nicer but more expensive) option, then the Wiseco 3.504" bore piston kit can be used with the K1 or Molnar rods. Lightwt forged piston, long rods, thin rings.....

Lou

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Home of Slant6-powered fun machines since 1988

Yes, the molnar rods are another very nice option,but for the best part of $900 for a set of rods and pistons its really beyond what I would be prepared to pay for a slant six street engine build,sure for a race engine that will likely break a rod it's a cheap investment and i wouldnt hesitate using them. But,the option of increasing comp ratio a little and gaining a larger bore all for the price of a replacement set of pistons is maybe more cost effective for my application,after all in most street builds guys use stock rods and cast pistons and work OK. The rod ratio thing is a very interesting topic,lots of theories ,but at the end of the day,look at say a 347 ford stroker,its just under 1.6 ratio from memory and will make 450 to 500 hp( and lots of torque) in hot street/ strip builds and never have an issue. The disadvantage of a long rod ratio in a long stroke engine like the slant is it increases piston dwell time at TDC,not great for detonation in a low rpm street engine,but the dish piston is supposedly able to improve combustion efficiency so its a bit of a trade off I guess... piston speed also increases for a given rpm due to the increased TDC/BDC dwell,again not ideal for a long stroke engine, certainly not a deal breaker ,the long rods do however favour small ports like the slant six,so there's a plus....at the end of the day if I needed the extra strength I'd buy the long rods in a heartbeat,but I'd rather keep the bucks down for my application. Cheers Steve

Sounds good.

Lou

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Home of Slant6-powered fun machines since 1988

i'm hoping it's not to late to jump into this tread? i to have been thinking about these holden 6 cyl pistons. i was hoping i could maybe use a 149 or was there a 161 cid as well ??? quite a few people have told me the racers used 186 pistons in the day but i don't really want to bore my std bore block that far, if i don't have to.

This thread was for alternate pistons for guys going all out with the max over bore...for a cruiser you can still get stock pistons in .020,.030,.040. and .060...and don't need to do a full over bore that will limit your block to no more overbores later... the alternate pistons for using the long rod build will over bore at .045 to start...

-D.Idiot

If your in Sydney have a talk to Col at Peak rebores in Peakhurst,he was the one who told me about the 173 pistons. If I recall he said the 171 or 186 were getting pretty big on the over bore,but I'm not familiar with the bore sizes of the other Holden's,I'm just repeating what he said to me. If your looking for a cam,I went to Pete Waggott in Alstonville,he does good work but it's going to be a regrind,Wade cams in Melbourne have billets and also do a good job,I believe they actually did the original "Pacer" cams in the day, to be honest I thought it was just a factory cam used,but other guys claim they used a local grind. I've got a fresh regrind cam here from Watsons,had it for years,it's only a mild 20/60 deal....but like I said in the diff post,give me a holler when you need any parts,I've got a few laying around,the local suppliers are way too expensive,I can also give you the names of a few USA suppliers that ship internationally,I bought a complete set of rod,main and cams bearings shipped to my door for less than a set of rod bearings from PPR!

FWIW Years ago Circle Track Magazine did a long rod / short rod back to back dyno test using the same everything else. The results were interesting. If long(er) rods are of interest I strongly suggest trying to find a copy of the article(s).

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Thom

Cross-threaded is tighter than Lock-tite