So I picked up a '64 2bbl 300 a few days ago and got it torn down. I reached out to an old contact and have a 4bbl aluminum manifold if I want if for a fair price (under $200). Here are two ideas I've been chewing on I'd appreciate some input on: Installing a Rover 4.6 crank and large journal chevy rods for a high boost build. The attraction to the Rover crank is that its nodular vs malleable iron, and you could end up with .100 larger rod journals with nearly the same stroke (Rover rod journals are 2.195). My question is, would it really be of significant benefit over the stock 300 crank? Idea #2 is use a 340 crank that's down the street that could be had for cheap, if not free. My question here is whether it would be possible to destroke with a Honda journal size rod (1.850) and avoid having to grind the rod bolts for cam clearance? Thanks.
Curious why you want larger rod journals? Are you referring to BBC or large journal sbc rods? There might be convenient selection with BBC 2.200 What are the initial thoughts on material differences? If boosted, how extensive of mods are you talking and what are the differences as an end result? What's cost difference with various levels of mods on each iteration? The cheek radius has tremendous influence on strength, sometimes more than material type depending on how it's used. If referring to grinding rod bolts, are you thinking of capscrews vs. rod and nut? What is the difference between the C to C distance on the Honda rod candidate and the current one? What is the existing clearance now? Why destroke if boosted?
Your rod bolt clearance issue is a function of the parts combination you end up with which includes the specific rods used, length of the rods, and the lift of the cam. Very likely only a couple of the rods will make contact, and unless you use a formula from someone who has already built the engine you won't know until it is assembled. The interference is at the upper shoulder of the rod. In my case I chamfered the ends of the rod bolts and lightly trimmed a spot on the shoulder of the rod to give .040" minimum rotating clearance. Didn't seem excessive to me, and was easy enough that I trimmed all the rods to match and chamfered all the upper rod bolts, in an effort to not upset the balance. I don't recall the exact details now but I doubt enough metal was removed to have much of an effect. In some combinations you will not have any interference at all. I was using long aftermarket rods with 3/8" capscrews. I would certainly not give up the extra stroke of the 340/350 crank because of it, plenty of 350s used that crank without issue and the only real difference is that they have a taller deck on the block. So more than anything else it depends on what rods you use. Also, the flywheel flanges are different. Makes a difference when flywheels can cost $400 each. Jim
Use the 340 crank . Don’t give up any stroke. Get different rods. Derek and Jim Blackwood I believe have experience in this swap
That's the way I'm leaning, thanks for all the input. I'm glad to know the rod bolt issue isn't as big of a deal as I was worried about. I'm thinking now about combining the two ideas and just setting up the stroker for a few pounds of boost to compensate for the poor flow head and intake flow. Jim, since you have experience in this, what static compression ratio would you recommend. As you can guess I'm planning nascar rods, likely with forged oversize 305 pistons.
Get the 340 crank and ADD .140" of stroke for a set of nascar 1.850" rods that are 6.200" long which should give you enough cam clearance without doing any grinding. The sbb 340/350 has a taller deck so to try and keep the piston weight down a close to stock length rod is a good idea to use for those 2 engines if those are the platform of choice. The sbb 300 with its shorter deck height the shorter more plentiful and often times less expensive 6.200" nascar take out rods are a good choice for the 300. With the shorter rod in basically the same clearance as the 340/350 engines the 6.200" rod will actuate more 90* from TDC away from where the cam clearance would be an issue. It will also dwell less on TDC and BDC than a 6.300" to 6.400" rod that would be used in a 340/350 stroker. Like how the General did with a factory sbc 400, they made the rods .135" shorter, instead of 5.700" they were 5.565". With the shorter rods and the 3.75" stroke in the sbc 400, the rod to cam clearance isn't an issue even with way higher than factory lift cams. Now when you swap in 5.700" rods, lobe lifts higher than around .330" which would be .500" with the standard factory rocker ratio or a small base circle cam would be required. With a 6.00" rod things get even tighter for cam clearance and a small base circle cam should be automatically be chosen from the start. With a 4.00" stroke combined with 6.00" rods in a sbc needs a small base circle cam AND clearance rods with a standard cam location block. IMO the sbb 300 is a better sbb to build a stroker with. If you want heads that flow, then the TA aluminum Rover heads would be the ticket for that platform. The only downside for the sbb 300 is no aftermarket intakes available for them, either a custom or factory. If you're looking at boost because the factory heads don't flow then perhaps what was going to be used to pay for your choice of boost poison could be put into a custom intake and the TA Rover heads and make a kick but N/A sbb stroker?(dealers choice) The porter that Dan Jones uses says he can eek out around 300 CFM(intake side) out of the TA Rover heads, out of the box they are IIRC 225 CFM on the intake side. With 300 CFM and a 362 stroker(3.800" bore and a 3.990" stroke) With 300 intake CFM has an N/A potential of 600+ HP!! Good question Bob. The crank's strength is probably lessoned but what's left of it is probably still fairly strong? If that is a concern there are bearings for a 2.750" crank available that could be made to work with a line bore to those bearings' housing bore size. Not as much as a 3.00" main but not as little as a 2.500" main either so............? PM me for these main bearing part #s if in you're interested? Another possibility is to stroke the sbb 300 crank from 3.400" to 3.540" for 321 cubes with a 3.800" bore and a 3.540" stroke. With this combo, cam clearance shouldn't be an issue even with the 6.450" nascar take out rods I have seen on eBay. Another possibility is to get a set of 5.900" Mitsubishi 1.771" journal rods and stroke the sbb 300 crank to 3.620" for a 328 cid sbb with a 3.800" .
The TA heads are no joke, I often wonder if the $1500 spent to get 64 heads to 200 intake and 150 exhaust would not be better spent on them. Then I remember that they are like 3k a set (iirc). I obviously have a lot of options as far as the rod length goes, I figure I would just use whatever length needed to get the cr correct with the 1.265 forged pistons. In response to a couple of f85's questions, nodular iron appears that it would be considerably stronger (30,000 vs 80,000 tensile from what I understand). Boost Performance out of the UK casts manifolds for a single or twin turbo setup specifically for the 64 and TVR heads. Yes, BBC as well as 2.1 SBC rod possibilites are attractive for the application. Destroking would be with the nonboosted setup mentioned in the first post. I just think its neat because if someone was really wanting to push the 300 that would be a great way to beef up the bottom end without shelling out for a billet crank. I talked to my friend about the 340 crank and the balancer would come with the crank.
In the bold, that would work as long as the rods you find have the correct wristpin diameter. If not a set of customizable AutoTec pistons would work great for what you're doing, I can PM the link if you're interested in them. Don't think you'll be able to fit a BBC rod in a sbb 300 without cam issues, but not sure because I never tried it? Maybe the 2.100" sbc rods you might have better luck making fit? Those 2 rod choices would get you closer to having cam to rod clearance issues even with a crank with a shorter stroke because they're wider bolt to bolt than the 2.00" rod journal rods. But might work if the stroke is close to as short as the sbb 300 factory crank? The BBC aftermarket rods for sure are wider bolt to bolt because most if not all of them use 7/16" bolts and the sbc rods that use the 7/16" bolts will be wider than the ones that come with the 3/8" bolts. The TA Rover heads pricing isn't in their website but is listed in their downloadable online catalog; TA 2150 PRICING Assembled $2,808.90 Bare Castings $1,500.00 $1,500 isn't to bad for the bare castings, if that's what they still cost? You'll need to call to make sure that pricing is still up to date? Cool project, I wish you the best of luck with it, if I can help in anyway feel free to ask. GL
I'm liking the idea of boring the mains to 2.75. I wonder what the cost is vs the extra grinding on the crank? The 4.6 crank only has a 3.22 stroke, so I'm inclined to think it would clear, but your guess is as good as mine. I also remember reading about timing some ARP main studs to some Dodge to fit in the 300 block, does that right any bells with anyone? The TA heads would be great for a "no expense spared" build". Mine is more of "exercise in frugality". Heck, by the time I get done pricing everything out I may rethink the whole bit, but the little stroker has been calling my name for a while now.
Usually much cheaper to grind more on the crank. There is more work than running a boring bar down the block...and should be a time to take advantage of other things while you're in there, like using steel caps/girdling for example. My understanding of the factory cranks is that there wasn't as tremendous of a difference regardless of stated material differences. There's a ton of misinformation about older iron, AFAIK. Overlap and corner radius are the biggies... and more importantly the general beef of the crank other than what appears on paper. I'm looking at a cast 1970 Olds 350 crank next to a forged 3.875 sbc stroker and there's no question that the Olds crank can take a serious beating. The sbc crank needs to be improved to handle the abuse, the other one is just plain stout. On that note...a cast 454 crank with 2.750 mains and 2.100 rods can easily handle 700 NA hp without much worry. Too much rpm will fling it apart though. I've run a stock low grade steel 454 crank at 900hp on Nos without much concern. The main caps wiggling around are more of a problem until the extra bolts are added. I think the crank's strength in this case isn't even on my list of concerns. What are we talking about here...a 650 hp engine on boost? I'd put as much stroke as you can fit and as short as rod as you can get away with along with as much flow as you can afford, with the emphasis on getting as much cross sectional area as possible out of the factory offerings. The engine will pump the top end harder, like it would with greater piston speed. It will drastically overcome the miniscule differences offered by the longer rods dwell effect at TDC. As far as I can tell, this isn't a lightweight super high rpm effort so I'd go the other way. Not sure what you are putting this in but the tiny blip of hp number at peak rpm is nothing compared to the raised torque curve along the entire way. The little bit of boost will match any hp peak seen by trying to rpm up a smaller pump.
I'm very much a fan of boost, even if it is only for the purpose of overcoming the shortcomings of head and intake. In fact that is how I built my 340, using aluminum 300 heads. CR is 10.6:1 , boost is 5-6lbs and performance is so far all I would ask for. So just looking at the numbers, say you had an intake flow of 135, if you add 5 psi boost that now becomes 180. Quite a significant improvement at a low boost level. It's just one way to attack the issue. Of course as the boost goes up the SCR needs to come down if the engine is to live. Jim
Duffey, Chris used Hemi main studs in his 300 Stroker. Had to be trimmed. I think if you call ARP and tell them you want main studs for the 300, They will give you 231 oddfire V6 studs with the extra ones needed.
Great to know, thanks for that! I think I found my combo. 340 crank with 6.2 nascar rods and Sil-vo-lite 1753H pistons would put me .020 in the hole before decking and about 11 to 1 cr. I'm thinking of keeping with the cheapskate approach and just build a simple, low rpm NA stump puller. Question is, can I buy 2 more pistons after the set of 6 or do I have to buy 12 pistons?
Duffey, Silvolite will sell you the 2 more you need. Single prices are higher. Holden (Australian GM) .905 pin. Did you figure the deep dish in your compression? If not, probably around 10.5.
Indeed--it would be about 10.5 if it was simply a dish (my math says it would be 12.6cc) but this piston has a raised center portion. I thinking by the looks of it the actual volume is close to 10cc, though I could definitly be wrong. Now that I'm thinking about it, that raised center just might cause valve interference... Might be back to the drawing board.
Duffey, What pin size is the Nascar rod? Is it bushed? I don't think you would have any valve clearance issues. Chris has 10.25 compression with a shallow dish and lots of clearance.
I have a zero deck, (+.008 actual with piston rock) and near .5" lift. Claying the valve/piston clearance showed nearly 1/4". No notches needed. 10.6 CR, .050" head gaskets. Jim
Oh good. The wrist pin hole is not bushed and is .827. I don't imagine it would be a problem to bore it out to .905?
