I'm starting to gather parts for a light rebuild of the 68' 307 I picked up a few weeks ago. Plans are to run a set of stock 1.94 fuelly heads, edelbrock 3 x 2 intake with Rochester carbs, stock bore/ original pistons, new rings, bearings, lifters, etc. I plan on using a 327/350 hp cam which in theory should give me a nice lope, good drivability and a nice powerband. Will be running a Saginaw 4spd, 3.73 rear in my 29' Chevy roadster. Any recommended cams you can give? How are the Elgin cams compared to the others?
Will those heads work on a 307 and not have an interference fit with the valves and combustion chamber possibly not fitting in the bore ??? I know 1.94 valved heads will fit on a 305. Just food for thought.
The 1.94 heads should be fine with the 307 bore, the 2.02 valves is where you'd probably start having issues. As far as a mechanical flat tappet cam, I want to avoid the h***le of weekly valve adjustment... I know there are hydraulic grinds out there that are similar to the L79 327 cam but with them there are slight differences in duration, lsa, etc so I'm looking for the best all around cam that's not going to bankrupt me. I see Elgin has a couple of grinds that look promising for a good price. Anyone have any recommendations on one of their cams?
Here is another option:http://www.summitracing.com/parts/hrs-cl110031-14/overview/make/chevrolet This is Howards L-79 repro and comes with matching lifters.The heads of choice for 307's are usually the 305 H.O. heads 416 castings, better compression than the 1.94 fuelly heads and have hardened valve seats.
Any cam up to .460 lift will do. Keep duration in the 212-218 range, the 1.94 valve will be fine. Super tune your combo to maximize power and fuel milage.
^^^ that avatar's famous around here I have a deep affection for the 30/30, & the second design '140' cams, legends in their time. Still, I'd probably opt for something in the hyd. variety these days. Lotsa choices these days, by many manufacturers.
It's a misconception that solid cams need constant valve adjustments. With a good set of adjusting nuts everything stays where you put it for a long time, hell, the first smallblocks came from the factory without hydraulics. However; IF you rev it to the stratosphere then things get banged around pretty good and more attention is needed. This is a situation you don't encounter with a hydraulic because they can't rev that high, but on the other hand,,, it's also a situation you don't get to experience! That said, your combination of a light car and descent gears makes a solid cam rather desirable. Another point; the exhaust seat recession issue only occurs when an engine is under at least 70% load for extended periods of time. This only happens in heavy vehicles and on the drag strip. It's not going to happen in a light car with descent gears. As far as the head choice; I like the look of the early heads without bolt holes. When I see a rod with late heads on the motor it just ruins it for me. I do think you should use a thin head gasket in an effort to gain a bit of compression and to tighten up the quench, but check your deck height and don't get it any tighter than .040. (Smokey said you can run it that tight and I have in a similar budget biuld ) If you do run the shim head gaskets, make sure everything is flat (a file run across the decks and the heads) and clean (lacquer thinner) and be sure to chase the threads in the block. Use spray Copper Coat on both sides of the gaskets and allow to dry. Put teflon thread sealant on the bolt threads. Warm motor without coolant (feel the end of the head) a couple times, then re-torque while cold. Then add coolant. Time tested method.
Call a couple of camshaft tech lines and ask what they would recommend for your combination. A Duntov 30-30 is way to big for that combo.
the hydraulic cam s dont put out power for **** go solid if you want some retching power and a 30-30 will work even with a stock converter IF THE ENGINE IS PROPERLY TUNED took me 2 days t o make it work and used a 6 cy conv nothing is simple in doing something like this you just dont throw a carb and dist in and drive out the door ,BUT IT CAN BE DONE
just bought a crate motor 350/290 hp changed out the cam put the GM 350/350 thats a good allaround cam
That sounds like some real 1962 thinking. Hydraulic camshafts have come a long way since the Beatles were still a local Liverpool band.
I don,t know how many cc's the 1.94 heads have but you might be making your c/r lower. Worth a check.
I have a 307 with -416 heads and a 262xe cam. It comes on really strong at 3000 RPM and has a slight lope at idle. Off idle performance leaves you wanting for cubic inches or a smaller cam. It's a terrible engine for the 73 C10 that it's in, but would do well in a 4 speed hot rod. Search "307 262xe" on YouTube if you want to see a video and hear what it sounds like.
I had good street performance using the Hyd. Chev 340hp/327 cam. Seldom ran it above 6K, and had fine midrange power, from 3500 up.
My wife thanks you although I'm puzzled at how he got that picture of her... lol Lot's of good suggestions. Keep em' coming guys...
Comp Cams Note this cam (671) is ground with the Intake CL at 108Deg, or 4 degree advanced GM Original L79 Camshaft Melling L79 Replacement Melling # : C-400-P 110 Intake Lobe Center Part Description : Camshaft Opens : 1 BTC/49 BBC Closes : 42 ABC/-6 ATC Duration : 223/223 Opens : 30 BTC/78 BBC Closes : 80 ABC/32 ATC Duration : 290/290 CamLift : .298/.298 Gross Valve Lift : .447/.447 Center Line C/L : 114/114 Rocker Arm Ratio : 1.5/1.5 Valve Lash Clearance : HYD/HYD Qty : 1 SHORT NOTES Part Notes : NOT CALIFORNIA COMPLIANT. Application Notes : W/SPEC. HI PERF. HYD. OEM #3863151 GM 350 290 HP Enlarge image [+] Part # 3896962 Hydraulic flat tappet Duration @ .050 Lift (deg): I: 222, E: 222 Maximum Lift (in) w/1.5 rocker: I: .450, E: .460 Lobe Centerlline (deg): 114 Technical Notes: Used in 290 HP 350 crate engine. Hoop
I ran an Isky 262, with .425 lift in a low compression 350 with 3 rochesters, in a 66 chevy c 10, and it ran great, good all around power and decent economy, and I wound it to about 6k regularly.
FWIW, I don't think you'll like those camel hump heads. The chamber size is too large and you'll have **** for compression. Look for something with a 58 cc head. With stock pistons, a shim gasket, and 58 cc chambers, you'll have near 9.5:1 compression. Have you looked into aluminum TPI Corvette heads? Thy have 58 cc chambers and flow pretty well. Around here you can usually find a set on CL in the 200-400$ range.
I don't want to ruin the look with a set of late model heads. The camel humps will be a huge improvement over the stock +76cc small valve heads currently on it. I realize I'm going to make sacrifices in torque and hp but I can live with that.
Don't forget to check seal to retainer clearance, most stock sbc heads only have room for .450" or so. And if they have no seals, just O-rings, it's the same deal, mush the seals or the O-rings out and you get smoke and a oily rear bumper. JW
Your call, but here's my take. If you paint the aluminum heads (or use the -416 305HO heads), there are going to be four people in the entire universe who are going to notice the accessory bolt holes. You've already crept into the "late model" SBC era by using a block with side engine mounts, so the gig is half-blown anyway. Besides, those accessory holes are an awfully convenient place to mount a sweet billet serpentine belt setup.
The old 350 hp/327 cam was 222 duration (at 0.050) and 0.447 lift. Equal on intake and exhaust. Don't know the LSA, but my guess is probably 108-110. It has a little bit of lope at idle, more on a smaller engine at 307 cubes. There are better modern design cams that tend to have split duration with a bit more exhaust which is generally good on factory heads and closed exhaust. I think you can do better with a cam around the same duration on intake, but maybe 230 on exhaust, and possibly up to 0.480 lift range. The lobe separation has a lot to do with exhaust sound at idle, low like 106-108 will have more overlap than the same cam with 114-116 separation, all else being the same. Tighter LSA will be more tough sounding idle exhaust tone, but a bit less low end torque. I would look for cam around 220-225 intake and 230-235 exhaust duration and 0.0.460-0.480 lift, and 112 LSA. Or close to that specs in general. Should rev to 6K easy, but still have sufficient low end. Although your lightweight roadster and 3.73 gears the low end is not so much concern. This cam will run nice with your combo and still have enough parking lot sound so it does not sound like a stocker.
It's a 307. Big-valve heads combined with every single cam recommended here is gonna KILL low end performance, and I guarantee you won't be happy with the top-end either. It's a 307, after all. I'm gonna ***ume you want to build a trad-looking motor for your car that needs to be driveable on cruise nights, at show, etc. Heads: Power pack 520 or 896 castings, or even the stock 293's, ***uming that's what's on it now, would be better suited than camel-humps. Smaller motor needs smaller ports...better port velocity= better performance. The Power packs were used on 327's and ran REALLY well. Replace the valves with a good set of 1.84 305 valves. Bigger isn't necessary-1.94's aren't going to flow much better because of proximity to the cylinder wall. Don't go crazy with valvesprings...the inexpensive z/28 types will be fine. CAM: Don't buy a 30-30 or L-79 grind. You'll hate it, because it won't have any power until it starts screaming. Don't buy any of the Comp Cams XE HE or whatever they're calling them now either. Save your money. One thing you do NOT want to do is over-cam your 307. Even a mild 350 cam with seem "bigger" in a small-displacement engine. Go cheap. Speed Pro's CS1014R would be as much cam as your street rod will ever need. Summit and Jeg's both sell similar grinds. All of them are cheap. Don't freak out because it's listed as an "RV/Towing" cam. It's a 307...it'll still seem like a performance cam in your combo, but it's not gonna rev to the moon. If you want more lope, lower the idle speed. Intake/Carb: Lots of choices.Stock 4bbl iron intake and Qjet (boring). Edelbrock Performer, Performer EPS or any of the similar aftermarket dual-planes would be optimal. Mate to a small vacuum-secondrary Holley and you're golden. Don't bother with the Performer RPM-you don't need it, and it'll lose power at low RPM over the smaller intakes. Port velocity is your friend. If you want an old-school single 4bbl, look for an Edelbrock C3B or C4B. The edelbrock 3x2 C357-B would be ok, but put a progressive linkage on it for sure. Exhaust: Make SURE to use headers with small primary tubes if you go with headers. Velocity is your friend. A set of the 2-1/2" Corvette Ram's Horn manifolds would work if you've got to fit exhaust under the car. They'll kill a little of the top-end power, but since you didn't over-cam it in the first place, it'll be fine-you arent building a drag car. Dorman makes repops for cheap. Don't get taken...90% of the "corvette" Ram's Horns you see for sale are the standard 2" outlets used on all the old SBC's. Have fun!
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