I've been gathring stuff for my ultra low buck digger engine. I'm pretty well fixed up for stock 354 stuff. I sure don't have everything. I'm going to be running alcohol so I want some pretty good static compression. I've got a set of domed 392 pistons that were milled down some. In the 354 they make less compression because of the lower swept volume. Looking at these pistons the pin height seems high. If I could find a longer rod I could get it up into the chamber and increase the compression. I'm pretty sure a Pontiac rod is almost a direct replacement for the 354 with the same 6.625 length, 2.25 rod journal, width, and pins. Looking on Ebay I found a guy selling various BBC h-beam rods for around $315. Lengths of 6.700, 6.800, and 6.900, rod journal 2.200 and a similar pin. I'm not sure about the width of the rod. Is this a crazy idea? It would get me into a much better rod and help the compression issue. For those of you saying "just get new pistons" forged ones like I'd need are upwords of $800. :-/ I like to look around and see what might fit and be different doing it. I
Kerry, If there's a will there's a way!!! I know what you are going through - I have FAR from the optimal compression in my digger for similar reasons - parts I had laying around so I used them. I like the idea of upgrading to a better rod. Watch your numbers - make it work!! How about some update pics????
Kerry Don't have my cheat sheet on the desk right now. BBC crank journal is somewhere close to right for ya? If the rods are too thick on the big end you should be able to shave 'em. I've had luck doing that before on a mul***ude of different combos, most recent was ford 300" 6 rods that went into an SBC. Anyway upgraded rods in a dragster is a good idea. You will also get more dwell time with the longer rods that adz up to beter fuel burning effeciency.
I've been pretty bad about taking pics of late. The ch***is is stripped and sitting on the trailer. I need to make a few plate pieces that will get welded in and then take her to my friend who is TIG welding it. What compression did you end up with? Yeah, the rod journal on the hemi is 2.250 and 2.200 on the BBC. The hemi's all have forged cranks so taking that much shouldn't be an issue. The width of the rod on the crank end might be an issue but I'm not sure yet.
Me Flat top pistons with adjusted deck height right @ 10:1 static. It was a real frankenstien, 400 block +.030, large journal 327 crank. The 350 that GM should have built. Loong rods = more dwell time @ TDC. More dwell time = less octain requirements or more effecient burn.
If your going to grind the crank .050 anyway you might as well offset grind it for what ever more stroke you can get and that will move the piston up some.
Hi Kerry, did you get my PM? Anyway, we run a 4 in bore 354. the rod journals are offset ground to BB chev journal size. Then just run a rod with BB chev big end. The offset is minimal so not much stroke increase. Negligible. We run Howards rods and Ross pistons. Yes they are not cheap, But we are inj on nitro. At least with the BB chev rod size bearings are cheap for chevs. are you going to run 354 heads? Your gonna hafta really work to get more that 11 or 11.5 to one comp out of it. Lippy
Cool combo, how's she working out for you? With these hemi's it's really hard to make static compression and still have valve room for a bunch of lift. Another reason I'm not wild about chasing new pistons. If I could find some better used ones I'd do it. I do have a set of used forged flattop 392 pistons that would be great in a 354 on fuel. Yeah, I'm tempted but I'm not going there.
Yeah Lippy. I made a reply, my computer ****ped out, and I decided to try again later. Great point about the stroke guys! Lippy, did you have to modify the rod width or pin bore? I am going to run 354 heads.
It's an animal on 85%. I am in no way trying to get you to run fuel, just trying to help with your alky deal. I'm not sure what your trying to do. What is it in? What trans, what gear, Ect...Injected?
Ok. The rods are custom alum. We run a .990 pin. The big end of the rods are made for the journal width. yes the forged 331-354 cranks are good ones. I know, I just broke one. LOL.
WOW! And that, folks, is why I'm not gonna run fuel! That and I can't afford it. ;-) I'm just goofing around Lippy. 3.70 gears with some 30" piecrusts. I've got a built up th350 I'm going to try to blow up. Yeah, yeah... I know. I'll be running a Hilborn 4 port on a 6/71 11% overdriven with a PG150a-1 pump. The cam is way to mild for this combo with 224 degrees and .501 lift @050 with a 112 lobe seperation. It is an Engle grind that takes advantage of the .904 lifter and has a pretty aggressive ramp.
It will work and be fun. Tighten up on the convertor, that will calm it down leaving. Bring it just above idle and nail it!! The 3.70's should be fine and help tame the launch also but should skidaddle on the big end. how fast do you want to run?
I'd like to see 150 but that might be wishful thinking with the piecrusts. A local buddy on the HAMB and I have been smack talking. Chicken has a Cad powered Model T that runs a 10 flat pretty consistantly. I'm gonna take him! ;-) The converter I have is a mystery 10" I gave $20 for. The first few tests ought to be interesting to say the least. Here's a pic of the ch***is as is sits on the trailer. The second pic is why I didn't bust my hump to finsh the stuff needed before going to the welder. That was taken Saturday. It'll be another couple of days before I get out of the shop.
You can send your crank to Henry at Velasco's and for about $300 he will offset grind it, polish it and nitride it! can't beat that!!
Jeez kerry, we got almost that much snow, not quite though!! That is a neat ch***is. You have a bender and all? Nice job. We run five spoke americans on the back, 15x13x33's. That thing will be a blast!! Whats the wb? You already have the trailer made!!!! Cool!
Not sure how much it amounted to. Somewhere between 14 and 18 inches. It's melting fast though. No bender. I looked real hard at one at last year's Springfield swap meet but $$$ was allocated for digger stuff. I did a LOT of chasing around to get the bends I wanted after I gave up on "fill with sand, heat, and bend" routine. I had lot's of places that I found to screw up my DOM. Finally had Ray @ H@L Metals do my back hoops. I need to measure to be sure exactly but it's a strong 120" wheelbase. Yeah, while I was going nuts trying to get the tubing bent I knocked out the trailer. I do need to wire it yet... and the wagon. I've not talked details to him yet but I'd planned to take my machine work to Engine Pro 5X over in Hillsboro. He's got a lot of race background and I think will enjoy my frankenstein engine project. BTW, what length are the BBC rods you are using in your 354? Stock pin height on the pistons?
Kerry, you can make most combo's work........Talk w/ your machinist.....price out your options....all that machine work required to make an odd setup work can add up real quick.......and sometimes you add up the parts and the machining bill......it can be greater than just buying the good forged pistons w/ the correct rod length and your done......I am a fan in building it once, even if it takes longer to go together because of cost....sometimes I look around at all the extra stuff I have hanging up and sell something to offset my costs and at times that has allowed me to build something right the first time and meet my goal....I know someone that threw together their 392 Hemi blown w/ cast pistons, because that's what they had laying around...I warned them.....one of the cast pistons gave up during a run....and it took out their hard to get 392 block..so really how far ahead was he?.....It cost him way more than just buying the correct part the first time....I am a fan of making the odd work......just put down all your options w/ cost on paper and go from their............Your frame looks great !..............Littleman
Very good point Littleman. I gotta ask the questions though. I'll let you all know where this takes me.
Hi Kerry: For what its worth you are not alone... Yep Pontiac Rods. Am doing some for mine. Got a Ebay deal on some BME's. Hot set up for an inexpensive Rod Bearing also.. The Pin is .984 for the Chrysler and .980 for the Pontiac so it needs to be cut. I will be Boring - Honing mine as .004 is a bit much to just hone out imo. ( I have Pistons already with a Hemi pin or I would have ordered otherwise) Good chance to check the lengths also. The side clearance needs some shaving but ya have to set it anyway depending on your application. Hopefully will be doing them soon. Also will be doing the slight modify to use 340 Main Bearings. Check the numbers... Your project is great. Doing a 331 for mine because thats the most parts I have to get together right now. Really would love to be using a few other items I have but oh well . Would rather be out slower then just sitting here on the HAMB and Nostalgia sites watching other people have fun.. Keep the Faith and keep us apprized of your work
Kerry and LZ, if you don't mind, I'd love to hear more on this. Is it applicable to 331,354 and 392's? What are the modifications?
I guess I should update this since I started this thread. My 392 pistons ended up having issues so I ended up buying some new ones. Since I was purchasing new I got them for the 354 and used some stock m***aged rods. The longblock is in the digger and I pre-oiled her a couple of evenings ago.
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