Guest Anonymous Posted November 15, 2001 Share Posted November 15, 2001 Yeah guys what's up, its me again... The guy with the crazy ideas... Since we had that big-ass discussion on 327 vs 350, and rod/stroke ratios, I've been looking at Various rod/piston combinations to increase the aforementioned ratio for my 327 build-up for very little outlay in $$, and here's what I came up with: #1 5.956" Ford 351W rods + 383 Pistons for 5.7" rod (compression height 1.433)... This leaves the piston 0.011" under the deck #2 6.135" BBC rods + 350 pistons with 6" rod (compression height 1.261) ... This leaves the piston 0.004" under the hole. On paper at least, #1 doesn't look like a very difficult swap. 351W rods are readily available, and they've got the same journal size (2.1") we have. I'm not sure the chevy rod journal is wide enough for these rods, but I'm sure the rods can be narrowed a bit to maintain proper rod side clearances. Anybody knows how much these puppies weigh? The little end will probably have to be reamed and bushed anyway, as the pistons I am looking at (Speed Pro H600P) have floating pins. And like I said, doing this swap removes the need to deck the block for proper quench (you would only need a slight clean-up, like 5 thou) saving yourself a $100 or so... So you end up with a better rod/stroke ratio, as well as lighter pistons (1.433 compression height versus 1.791) for reduced reciprocating mass where it counts most... At the piston. Plus it should end up costing more or less the same as a regular 5.7/327 combo. As for option #2, it will probably be more expensive due to the need for bearing spacers, and more expensive pistons. And I've got the same concerns as to whether or not they would fit on the journal... BBC rods are cheap and plentiful, not to mention STRONG. However they are pretty hefty... So you get an even better rod/stroke ratio (1.89 vs. 1.83) as well as an even lighter piston for less reciprocating mass, but this is partially offset by the heavier rod) On paper, I am leaning more towards option #1 and would like to hear more thoughts about this... What do you guys make of all this? Is my logic flawed here? Have I hit the crack pipe one too many times? Thanks! Quote Link to comment Share on other sites More sharing options...
Peternell Posted November 15, 2001 Share Posted November 15, 2001 Call me crazy but I'm gonna try these rods. 6" fully prepped rods w/ARP Waveloc bolts for $175.00 to your door. http://cgi.ebay.com/ebaymotors/aw-cgi/ebayISAPI.dll?ViewItem&item=597876611&r=0&t=0 What would the ARP bolts, hone and bush and resize cost for the 351 rods? A friend built an oddball stroke Ford ( I mention this cause your considering Ford rods) and used Mopar 340 rods (6.125"). These have similar side widths to the Chevy rods. Another option seems to be the Ford 300 6-banager rods, which are 6" and can be had cheap! Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted November 15, 2001 Share Posted November 15, 2001 I'm assuming here, as per your opening statement, that your basically wanting to alter you rod/stroke ratio; here's another idea concerning the squish issue. What about using your stock length rods & buy forged pop-up's...then have the pop=up's milled down to your .005-.010" piston deck to block deck tolerance required. Just depends on budget & how you wish to approach the matter. Either way; machine work is required & your product is only as good as the machinest performing the work; so cost is directly parallel to the expertise of the machinest regardless of which choice you make. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 16, 2001 Share Posted November 16, 2001 I was mistaken about the 351W rod journal diameter, it is 2.311" and not 2.1" The reason the mopar/ford rod swap worked was because the mopar has a smaller (2.25") rod journal diameter that could be bored out to fit the ford journals, however, it is too big for our purposes. Also I think the BBC rod swap is out for that very same reason... There are no bearing spacers available to adapt the 2.25" rods to a 2.1" journal... However I have come up with a few other rod/piston combinations that might prove handy... Stay tuned for more Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 16, 2001 Share Posted November 16, 2001 Aight... Here's the beef - Buick V6 rods from a 181?,196, 225, 231, or a 252. These are readily available, are 5.960" in length and come in 2.1" and 2.25" rod journal diameters... I don't know which ones come with what exactly, and whether or not they've got the proper rod width, but hopefully, one of you guys do. Would these make a good fit? They are cheap, close to ideal as far as length is concered. Now if only they could be made to fit... - 6" Olds rods out of a 307,330,350,403 These came with both a 2" and a 2.125" rod journal diameter and could be made to fit either way. Again, I don't know about their rod width or small end diameter, so again, I'm hoping you guys will be able to fill me in... I'd really appreciate it. One more thing, with a 6" rod and 383 pistons for 5.7", if we deck the top by 5 thou to clean it up, the pistons end up sticking 0.038" out of their bores. So would it be feasable to mill the pistons by that much to compensate? Or would that weaken them too much? The other thing I could do would be to offset grind the crank, but that would be pretty expensive (I would mill the pistons myself if I had to) not to mention I'd lose a couple cubes Again, the reason I want to stick with these pistons is that they can be had for at least $100 cheaper than 6" 327 pistons due to a much greater demand for them. Plenty of people go for 383/5.7" combos, whereas 327 builds are relatively rare, let alone ones with a 6" rod, this reflects in the difference in price... Hopefully I'll get some feedback on this, as I haven't gotten much love over at Chevytalk yet! Thanks Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 17, 2001 Share Posted November 17, 2001 didnt some one use ford 300 6cyl. rods on a sbc build up.........400 block and 327 crank...about 350 if i remember right(the 350 chevy should have built!) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 18, 2001 Share Posted November 18, 2001 Yes, but they had to use custom pistons which cost them a pretty penny. Thank God for mass production! Quote Link to comment Share on other sites More sharing options...
Guest Thurem Posted November 18, 2001 Share Posted November 18, 2001 Just took apart a Yamaha Virago 1100 motor, it has approximately 6 inch rods, and beefy looking. Good luck finding four of those motors to strip the rods, and I don't know the holesize either. Thure Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 19, 2001 Share Posted November 19, 2001 Hey just as a comment, havent really worked the numbers yet or the $$$ but i think the ultimate rod to stroke combo would be if you used a 400 block , a 2.70" stroke crank, (just saw an unmachined forged crank part# in a chev hi-po book) with some 6.125 rods and pistons with a comp height of 1.55! talk about a smooth motor! only 288 ci ! but it'd probably rev as well as a honda! Dan Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 19, 2001 Share Posted November 19, 2001 Can I get extra-thick head gaskets for the SBC?How about if I just stack head gaskets on top of each other, any adverse effects to that? And which would be preferable for this? composition gaskets, stainless shim, or copper? Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted November 19, 2001 Share Posted November 19, 2001 Omar, I have seen decompression plates on turbo engines and these have head gaskets on both sides. I wouldnt be stacking gaskets myself. Douglas Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 19, 2001 Share Posted November 19, 2001 You can stack steel metal shim gaskets. I think the thickest is 0.022" Also take a look at the copper sheet gaskets. You may be able to stack those as well. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 20, 2001 Share Posted November 20, 2001 Omar your quench distance MUST be close to .040 thousands if you go more or less by more than .005 thousnds you are more prone to detonation or piston to head contact.btw http://cgi.ebay.com/ebaymotors/aw-cgi/eBayISAPI.dll?ViewItem&item=598180475 get these rods there is no way you will beat the price after you add machineing to any other rods Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 20, 2001 Share Posted November 20, 2001 Yeah you guys are right, these rods are incredibly good value, plus they weigh 560g (compared to ~600g for a stock rod) despite the fact that they are 0.3" longer. And I'm sure they can be further lightened by beam polishing etc This leaves us with the problem of maintaining the correct quench (0.035-0.040") distance, as well as preventing piston to head contact Using 383 pistons, this leaves us with the pistons sticking between .025 and .033" out of the hole, depending on compression height. And that is before any cleanup cuts on the deck surface or heads. so to acheive proper quench, I'm gonna have to do the following: Use extra thick head gaskets, or stack head gaskets... Can I mix composite and metal shim gaskets? What's the maximum thickness I can go to? Mill the pistons some... Not too hard (or is it?), I can probably do it myself using our machine shop. What's the max I can go with Hyper pistons? What about Forged pistons? Offset grind the crank to reduce the stroke to 3.2 or 3.22". Problem is this is expensive... What I'm thinking of doing is milling the pistons a bit, and using thick head gaskets (or stacking) to achieve proper clearance... So what would be best here? How thick can I go, and how much can I safely mill? Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 20, 2001 Share Posted November 20, 2001 K B pistons makes a set of matching pistons and they are no expensive 1-775-887-2971 #kb154 (8.5-10.4 cpr depending on head voluum)thats a 327 piston for a 6" rod or KB 155 (9.4-11.8) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 20, 2001 Share Posted November 20, 2001 Again, 383 pistons are much more readily available on ebay, swap meets, etc. This is how I am sourcing most of my parts. I just never pay retail The KB pistons would go for around $250-280 depending on who you talk to, whereas I can get 383 pistons for $100-150 which is more like it... The original point of all this was to get a better rod/stroke without paying much more than I would going with the 5.7" rods. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 20, 2001 Share Posted November 20, 2001 omar by the time you pay for those 383 pistons and also pay for a machine shop to surface the decks(which can weaken the pistons ) you will spend more $$ and have less strength than doing the job correctly in the first place!! Quote Link to comment Share on other sites More sharing options...
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