Hey guys.
If this has been done before, i'm sorry. I wasn't able to find it.

My question is this ... I'm about to do a couple of upgrades to my car to drive until I drop in a 468 next year. I've some a fresh set of camel hump heads, an Edelbrock Performer RPM intake, headers, an HEI distributor and a few bling bling things to put on the car.

The motor in this car is the 210 hp LF7 motor and the cam is the .929 cam?? I've read that they didn't spec the cams the same way back then and I was wondering what was a comparable cam today? Also, with the stock cam (if it's in good shape) would a set of roller tip rockers help? I've found a set that are 1.6 vs the stock 1.5s. Just wondering if that .5% increase is worth the trouble?

Or should I just pull the damn thing and rebuild it? I was trying to just do a top end kit (heads, intake, 650 cm carb, headers, distrib) and I've got a Jackson gear drive set I was going to install, but I'm not sure my wife would appreciate it.

 

I would do this much and go for it.
-929 camshaft is the stock-est cam GM made - gazillion of them out there, er, used to be - 194°/202°(?) adv duration, 118° LSA, .390" int/.410" lift.


Leave rockers in other guy's garage.
If not presently burning oil, leave the block the way it is.
If it ain't broke, don't fix it.
JMT's

 

Forgot in adding, unless you want gear noise, leave the PJ gear drive on the shelf.
Check chain looseness and if over 10° of slack, replace with aftermarket roller chain.
Maybe, if the engine runs good as it sets, leave it alone.

 

Everett#2390,
Thanks man. Now that I read this I seem to remember the .390/.410 numbers. I wrote all this down at one point, but my office is a mess.

Yes, I'd like to do the bare minimum for now as I remember hearing the 210-275 motors had the same lower end (or short block) and the heads, intake, carb were the big difference?

Either way, If I can just swap it out and have a solid 275-300 hp motor? I've also got a rebuilt turbo 350 tranny to swap out the power glide. I'm hoping I will see a good amount of difference.

4 whl disc brakes and suspension stuff is also in the garage, but that can wait as far as I'm concerned. Or at least until I pull it apart for the Big Block swap.

Thanks again.

 

Oh, also, the pistons in these motors. Dish? I'm sure they aren't a "flat top" which I can get if I find something I don't like when I pull the heads off.

Thanks man

 

Well my research showed that the ONLY difference is the heads, intake and carb. The pistons were the same I'm pretty sure, but the heads on the 275 hp. had a 63cc (I think) chamber giving it a 10:1 compression ratio.

I have the same engine. My plan is to go with the AFR heads, better cam (probably a roller) intake, carb and headers. My goal is to get at least reasonably close to 400HP, then decide if I want to change over to a 400 + ci engine and go for over 500 hp.

 

I was more or less correct. The timing curve was different also.

The L30 option16 began by replacing the standard intake and 2-barrel Rochester down-draft carburetor of the baseline 327ci-210HP engine with a 750 cfm 4-barrel Rochester Quadra-Jet carburetor (four possible carburetors in 1967: 7027203 (early) or 7027213 (late) without A.I.R., or 7037203 (early) 7037213 (late) with A.I.R.; in 1968 there was only one carburetor for this application: 7028213) containing a 0.071-inch main metering jet and mounted to a cast iron double-deck intake manifold (part numbers 3905393 in 1967 and 3919803 in 1968). To this was added (as shown in the cylinder head table below) higher-performance cylinder heads (retaining the hydraulic lifters) that increased the base compression ratio from 8.75:1 to 10.0:1 and contained larger valves for improved fuel/air flow. A different distributor advance optimized the power curve.

Quadra-Jet Saginaw/Muncie 4-speeds
The Rochester Quadra-Jet carburetor was used on both L30 and L48. Top: Saginaw 4-speed, available with L30.
Bottom: Muncie 4-speed, available with L48.


L30 engine, underhood
A 1967 L30 (with 1967 manual transmission
smog equipment) engine.
The L30 engine design is functionally very similar to its progeny, the L48; in most cases they used the same components. In reality, the L48 engine is best described as a long-stroke L30! Both engines shared the same block castings (usually), heads, intake manifold, exhaust manifolds, camshaft, and carburetor. The L48 got its 20 extra gross horsepower almost exclusively from the 23 extra cubic inches resulting from the longer stroke, though the fractionally higher compression ratio (10.25:1 as compared to 10.0:1), a byproduct of the change in stroke and piston compression height, was a marginal aid.17 The L48 crankshaft was obviously different due the longer stroke; less obviously different were the pistons. The pistons from both engines were similar in design; both being flat-head, slipper-skirted, pressed-pin, cast aluminum-alloy pistons with valve relief's on the head. The main difference between the pistons was simply the compression height (changed in the L48 from 1.675 inch to 1.565 inch, to accommodate the change in stroke), which caused other related cascading minor changes in the piston geometry. Rods were 5.7-inch long and of forged steel in both engines.

The 1967 small-journal L30 crankshaft, casting PN 3884577, was forged steel as was the L48 crankshaft. In 1968, the large-journal L30 crankshaft material was switched to nodular cast-iron, casting PN 3941174. L48 used casting PN 3892690 in 1967 and PN 3941182 in 1968),18 with premium aluminum-alloy steel-backed bearings, upgraded from the copper-lead or Babbitt-metal steel-backed bearings used in the base 327ci-210HP engine. In 1967 Chevrolet began transitioning to a larger main bearing journal in its small-block engines. The new 350 engine was the first to receive the 2.45-inch journal. The remaining small-block engines, including the L30, did not upgrade from the 2.30-inch journal size until the 1968 model year.

Both the L30 and the L48 used the same, relatively mild, camshaft for both years (3896929 machining part number, 3896930 casting) that had a 0.390/0.410-inch intake/exhaust lift and a 310/320 degree intake/exhaust total duration using a 1.50 rocker ratio. Because of the slightly different power curves, different distributor advance settings were selected resulting in different distributor part numbers:
L30 used 1111249 and 1111298 in 1967 and 1968, respectively;
L48 used 1111168 and 1111264 in 1967 and 1968, respectively.

 

Wow, right on Coach62.
I've got enough stuff here to make a reasonably "fun" 375-400 motor while I finish up on the last few things on the 468 motor sitting in my shop.
Good article out there to make 462 hp with the AFR heads and some changes. I of course just bought these 462s so going for some aluminum heads is out of my budget.

So next weekend (yes, Christmas weekend) I'll pull the A.I.R. smog system off, then the manifold with carb, and finally the heads and make sure there is nothing "ugly" under there, get a good look at the cylinders & pistons and then slap on the new top end and call it a day. The new HEI distrib should take care of a few things.

I'm very excited to get this car on the road for a long term kick azz fun time while I find any and all the parts to complete a nice G-machine / pro-touring ride.

 

You're welcome, obviously I've been researching the same thing.

Care to share the article? I assume it's not 462 HP from a 327?? Could be done for sure, just not sure I'd want to beat on my "born with" 327 that hard. It never did nuthin to me.

Like the saying goes; No such thing as too much anything.

 

462 = last three digits of head casting number
Same for 451, 461X, 492, 292, 186, 094,