A guide to building the lil guy. The Mighty 300

Discussion in 'Small Block Tech' started by Joe65SkylarkGS, Oct 27, 2009.

  1. Jim Blackwood

    Jim Blackwood Well-Known Member

    Thanks, I've not counted them out by any means, just want to be sure I'm doing the right thing when the time comes. Buying the bare heads will be a bit of a stretch to begin with, I'm sure most here can relate. But, one I might be able to justify. Sort of similar in some ways to the custom pistons. But to do those things I have to find other ways to economize. So obviously I'm looking for the best ways to do that without cutting corners. I'm really not a fan of chevy's stud-n-ball rockers, especially not after someone on here tried to adapt them to a SBB with a mounting plate and proceeded to break things due to flex. I saw that one coming. But they can and do work if the heads are made for them and if that's the only inexpensive option... Might need to keep looking into the paired shaft rockers though. Olds used an interesting variation on that theme on their 350.

  2. Dan Jones

    Dan Jones Well-Known Member


    I have ported Buick 300 aluminum heads with 6000 Series Ferrea Buick V6 Stage 1 stainless steel valves, shaft mounted roller rockers and D&D end stands, along with a bare set of TA Performance heads that I'd sell. I also have both a bare and an assembled set of Buick 300 heads that I'd sell.

    > I'm really not a fan of chevy's stud-n-ball rockers

    You don't have to use those with the TA heads. They also accept conventional guide plate and stud (3/8" or 7/16") mounted roller rockers just like most aftermarket SBC and SBF heads. Note that TA calls the stud mount roller rockers "shaft" in their catalog for some reason. They also refer to the stud mount rockers as pedestal mount even though pedestal mount rockers generally refer to bolt down rockers using a smaller 5/16" bolt.

    > Might need to keep looking into the paired shaft rockers though.

    Yella Terra in Australia makes those in a variety of ratios, including shorter exhaust pairs (e.g. 1.65:1 intake and 1.55:1 exhaust). Since the exhaust is under cylinder pressure, it's relatively insensitive to valve acceleration but is sensitive to duration. We've seen better average power with a shorter exhaust ratio on some engines. Yella Terra's online prices are high but places like carshopinc.com good have better prices. I've not measured the TA head stud centerlines to see if they are the same as the SBC, though. I'll put that on my list of things to do.

    > Art has some roller blanks already made up.

    What sort of cam specs are you looking for? Note that Art's blanks are full round lobe cores which are quite expensive to finish machine. Woody had some pre-shaped roller cores made that work with the conventional front cover and only need minor finishing but are limited to the range of duration, lift and LSA. Woody's lobes are nominally 250 degrees @ 0.050, 0.550" lift and 110 LSA but the LSA can be altered +/-2 degrees (108 to 112), duration +/-30 degrees with a minimum lift is in the 0.510" to 0.520" range. Note that if you're at the extreme of one parameter like LSA, you can't be at the extreme of another like lift or duration. I've got one of Art's roller blanks and it's still cheaper to use one of Woody pre-finished cores. TA has similar pre-finished roller cam cores.

    > I'm inclined to stick with the shaft style rockers because they are inherently more rigid than stud mount

    As others have noted, the OEM Buick/Rover rocker shafts won't work due to the valve spacing. The dedicated rockershaft system for the TA heads is expensive. The optional stud mount is plenty rigid for most applications and much less expensive. Also, the SBC style stud mount rockers are available in a variety or rocker ratios. TA recommended 1.65:1.

    > the advantage of the roller cam as I understand it is that the profile can provide both better top end and better idle than a
    > flat tappet is capable of. Do you guys have any verification of that theory?

    A flat tappet cam has higher acceleration off the seat but cannot sustain as high a velocity as a roller cam can. When hydraulic rollers were first introduced, it was claimed the cross over point was around 270 degrees seat duration (below 270 degrees, a flat tappet could make more power) but some cam grinders claim that is no longer the case and rollers are better even for very short duration cams. Given the Buick/Rover small lifter diameter and base circle, it has particularly low flat tappet velocity limits. Some claim the friction reduction with rollers is enough to lower running temperature but I've never tested that claim. OEM Buick 215/300 and Rover reach maximum flow at a relatively low lift so don't need or benefit from a bunch of lift but the TA Performance heads keep increasing flow to much higher valve lifts. I'd definitely run a roller cam (and a bit larger rocker ratio) with the TA heads.

    Wear becomes an issue with flat tappet cams, especially with the very small Buick/Rover cam base circle. For a flat tappet, wear is pretty much a function of load at the pressure line. More aggressive flat tappet lobes need more spring pressure which means more wear. I've got a quarter million miles on one hydraulic roller cam (with 1.7:1 ratio rockers and stiff springs) and the lobes have next to no wear.

    > You think it makes enough sense to go to the trouble?

    Having suffered more than one flat tappet lobe failure, I always opt for a roller when I can though I do have one Rover 4.2L build (with ported Rover heads) going together with a solid flat tappet.

    Dan Jones
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  3. Jim Blackwood

    Jim Blackwood Well-Known Member

    Thanks Dan, I appreciate the post. Lots of good info there and I'll be getting in touch to talk about some options in due course. (But don't wait on me naturally.) First step is to get the engine down here from Pete's place out in Illinois, break it down and see what I've got, so my guess is that it'll be along towards the end of next summer likely as not. I'll do what I can to square away the more transient purchases early though, and eventually I would like to talk with you about cam profiles. For now though as a reference point I'm thinking probably something about like a CC 268H profile should work. Maybe go for a little better idle.

  4. Dan Jones

    Dan Jones Well-Known Member

    > First step is to get the engine down here from Pete's place out in Illinois

    What part of Illinois? I'm quite close to southwest Illinois (e.g. Alton, Illinois).

    > eventually I would like to talk with you about cam profiles. For now though as a reference point I'm thinking probably something about like a CC 268H profile should work. Maybe go for a little better idle.

    Shouldn't be a problem. The CC 268H is a very mild lobe which can be improved upon for your application. Cam specs will depend upon which heads you end up going with.

    Dan Jones
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  5. Jim Blackwood

    Jim Blackwood Well-Known Member

    Pete lives in Sydney, straight shot west from Indy. I'll have to come up with an excuse to visit him and Rick, don't know right now what that would be though. Picking up an engine maybe.

  6. Bzltyr

    Bzltyr Member


    Do you still have heads for sale?
  7. Jim Blackwood

    Jim Blackwood Well-Known Member

    As an update I now have a 300 block on the stand with a 340 crank sitting in it, mains turned down to .030" oversize and will go to standard at regrind, probably .020" under on the rods (-.010" now). I also have a 340 block on another stand holding up aluminum 300 heads and a 300 intake. Shopping for a set of light forged rods 6.3-6.4" long, maybe something out of a SBC in the $200-300 price range. I have 2 sets of 300 heads but may sell those to help finance the purchase of a set of TA Rover heads. No hurry on that. I may eventually sell the alloy 300 4bbl intake as well.

    The 2bbl intake is going to be turned into a blower intake for an Eaton M-112 (Ford Lightning) and will get intake spacers to bolt it to the 340 (eliminating the intercooler and lowering the inlet scoop, at 5 psi boost it is just going along for the ride, adding weight and obscuring the view and more power is not needed). Then after the 300 is built it will go there. At that point I may sell the 340 either as a short block or with the alloy 300 heads, and possibly with the alloy 300 4bbl intake and spacers.

    I have learned that using light weight rods and pistons plus an aluminum flywheel in the SBB (3.850" stroke) makes for an extremely responsive engine that really likes to rev. So much for that long stroke lazy engine myth. It's not even remotely lazy. Need better valve springs but hey, one thing at a time right?

    Harlockssx and 300sbb_overkill like this.
  8. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    You're going to have a hard time finding that unicorn set of rods for that price. The longest 2.00" rod journal sbc rods I have ever found is an Eagle H-beam 6.125", which would work for your application but are about 130 grams each heavier than typical nascar take outs. I think they do sell an LS series rod with an 1.889" rod journal size that is 6.300" but are much more than what you want to pay.

    Nope, just looked, they sell 6.460" and 6.560" long rods for the 1.889" rod journal size for the LS engines;


    But they do sell the 6.300" long rods in the sbc line with the 1.889" rod journal size and the 6.125" long rods for the 2.00" journal size are also listed here;


    You can get the Eagle rods for less $ from one of their distributors than buying direct from Eagle if you go that way.

    The rods below have the 2.008" housing bore that have 1.889" rod journal bearings and 1.850" rod journal bearings available for them.


    With the sbb 300 block with its lower deck height you can get away with a 6.200" rod. The shorter the rods the more it will actuate away from the cam.

    Here's a better set of 6.200" rods with forced EDM wristpin oiling for $24 more;


    They wrote that they have 2.010" housing bore, I would have to say someone that doesn't know what the housing bores are supposed to be, measured one rod with calipers and rounded up what should be 2.008" to 2.010". Anyway these should have the same 2.008" housing bore that the 6.350" rods I gave you a link too have, that has the 2 rod journal bearing sizes for. Or they could be the 2.015" housing bore size that only have the 1.889" rod bearings available for them? You might have to email them to confirm if you're interested in the 1.850" rod journal size, otherwise wait til you have them in hand so you can measure them before you order bearings.

    There are lots more of the 6.200" nascar take outs on eBay that are the most plentiful size and the least expensive. Just so you know that they will hold up for you, gsjohnny runs the 1.889" rod journal size nascar take out rods with the standard Buick 3.850" stroke(not necessarily the 6.200" length though) on his supercharged sbb 350, so they should hold up just as good for your app.

    You're only talking a .0562:1 less rod ratio going from a 6.400" rod to a 6.200" rod. 1.662:1 with 6.400" to 1.610:1 with 6.200" with the standard 3.850" sbb 340/350 stroke. With 6.300" in the middle @ 1.636:1. A teeny tiny amount of more rod ratio, or more cam clearance? Dealers choice, I hope this post is helpful.
  9. Jim Blackwood

    Jim Blackwood Well-Known Member

    It is helpful Derek, most of your posts are.
    The most sensible thing is probably going to be using the 6.2" Nascar take-outs and then make up the difference in the pistons. Plenty of room for the rings that way. Personally I think the reciprocating weight probably trumps the rod ratio anyway. Might be putting it on hold for a bit though so I can buy a couple of new wheels and tires, plus I need to order some aluminum bar stock for those manifold spacers. However, if I do run across an especially good deal I just might have to jump on it.

  10. Bzltyr

    Bzltyr Member

    I have a cad drawing for intake spacer for the 300 aluminum heads.
  11. Jim Blackwood

    Jim Blackwood Well-Known Member

    That could be useful. Is it to go from the 300 to the 215 intake, or to fit the 300 intake to the 340? Difference in thickness of about 1/16".
  12. Bzltyr

    Bzltyr Member

    I am actually installing the heads on a 1965 300 and using a Rover intake so I can go to fuel injection. With just a little taken off the head and a little off the block and using a 0.050 thick head gasket a 3/4" plate seems to be perfect.

    The cad drawing changes due to the thickness. Mostly the bolt holes.
  13. Jim Blackwood

    Jim Blackwood Well-Known Member

    Do you think you could attach the file to a post here?
  14. Bzltyr

    Bzltyr Member

    Sure. It is a work in process. I have elongated the holes for the use of 3/4" spacer. They would not need to be quite so large if the spacer is thinner. I had to make the openings for the intake port and water jacket because water jet cuts straight through. There will be a lot of grinding to port match because of this. I am talking with a water jet cutter to try to get them to cut the spacers on an angle. The problem there is the perimeter will have to be on the same angle - not good.
    The perimeter comes close to matching the Rover intake. I do not know what the perimeter of your intake will be. I will attach it and you can let me know you have any suggestions or improvements.

    I tried to upload the file but it said the extension is not allowed.
    PM me for my email.
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  15. Bzltyr

    Bzltyr Member

    Some pix. 300 Buick-01.jpg 300 Buick-02.jpg 300 Buick-03.jpg 300 Buick-04.jpg 300 Buick-05.jpg
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  16. Jim Nichols

    Jim Nichols Well-Known Member

    Sean Etson years ago used spacers that were 1/2" thick. He may have used thicker gaskets. Maybe you are using RTV instead. Are you sure your spacers aren't 5/8" ? Here are pics of his setup from this site:

    int.2.jpg int.7.jpg intake plan.jpg
  17. Jim Blackwood

    Jim Blackwood Well-Known Member

    A set of 4 Buick wrist pins laid on the side spaces the 300 (alloy) intake up from the 300 (alloy) heads on the 340 block with .040" MLS head gaskets just right to center the bolts in the holes on the intake.

    From that I calculated a .610" spacer with 2 gaskets (.040" ea) and my 1/4" tray which includes the ports and an RTV or Right Stuff sealant to the heads and block works out just about right.
    .940 which is the diameter of the wrist pin. So .625 will work for this.

    The difference in deck height of 300 to 340 is .650" and from 215 to 300 is .540". Just based on that I would expect about a 3/4" spacer to work for using the Rover intake on the 300, but you never know for sure until you try it. (or actually calculate the trig functions instead of estimating) The file Bradley sent me was configured for a 3/4" thick spacer. I don't remember if he said how close it came out.


  18. Bzltyr

    Bzltyr Member

    The 3/4" spacer fit very well.
  19. Jim Nichols

    Jim Nichols Well-Known Member

    Bradley, did you use a gasket or sealant on each side of the spacer?
  20. Bzltyr

    Bzltyr Member

    I have not gotten the engine altogether yet. I expect gaskets will be enough.

    I am looking for a set of heads right now. I am hopeful Dan Jones has a set.

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