The Money Pit

I normally don't post here,but decided to give it a go.

I've built a fairly stout 406 smallblock,and it's been a long slow process of trying this and that,changing cams,intakes,carbs,etc. It occurred to me with the current setup I've built totally by accident a "little brother" version of the L-88. My cam is a solid Isky Z-35 which has 254@.050,and lifts .560 with a 108 LC. I'm running AFR 195 heads and a port matched Victor Jr,with a "tweaked" Holley 3310 carb.All said I'm pretty happy with the power,as it'll pull to 7000 rpms. The idle is a another story.

I was wondering how the real L-88 was as far as driving manners on the low end. From what I gathered it was good for 550-570 hp on the top,and I'm estimating mine to be around 540 hp.

rongold

Back in 1968, at age 21, I bought a brand new L-72 427/425HP Impala with a C/R 4 speed and a 4.10 rear--great combo for that engine. It ran very well. At about 22,000 miles, it started to burn oil, knock, and foul plugs. I pulled the engine, and rebuilt it to closed chamber L-88 specs---pistons, rods, cam, etc.--everything except aluminum heads. I also had it bored .060, which increased the displacement to 440 cubic inches.

WHAT A DOG IT TURNED OUT TO BE. It sounded great, but didn't make any power until it hit about 4,000 RPM's. I sold it soon after that. It was barely drivable on the street. So, if anyone is thinking of even just putting an L-88 cam in their 425 or 435 HP engines, don't do it unless you have at least 4.88 gears---you won't like it.

RON

JohnZ

The terms "L-88" and "driving manners on the low end" are mutually exclusive; can't imagine anything worse for street driveability than an L-88.

ghoastrider1

5 oclock rush hour...brrrrrrr.gives me shivers thinking about it.

The Money Pit

So the lack of power brakes,stalling at idle,13-14 mpg would be "L-88 normal"?If so I guess I'm done "tuning".Might have to swap in a smaller cam,and throw the dual plane intake back on.

Glenn's 67 BB Vert

they didn't call them "race motors" for nothing?? I had a pretty much stock 1970 LT-1 (370hp) in my 64 and still got 20 mpg awhile back--Glenn

bb62

13-14mpg LOL, more like 13-14mpg/2

If I got 13/14 mpg with my L71 that would be a miracle, never mind an L88

Ironcross

The only thing keeping mine off the road is the gas consumption, 7-8 MPG and cost for 100+ octane let alone find it in a service station. I put 28,000 miles on a correct "IT" engine before it needed to come apart. It will be going back in the 68 next week after 34 years setting on the side. I also use a LS7 on the street which to me is the smog equivalent of the L88. Just don't have one Vette to use these engines or it will get old hat quickly with the high cost of fuel. Today they are just toys for occasional use. When new, the L88 was a daily driver. Hell I like them so much I even stuffed two in a 18 foot drag boat.

vetrod62

How about a 350 ci. , 284* roller at .050, tunnel ram with 2 hemi race carbs. It would foul the plugs if it idled for more than 30 seconds. Spit and buck under 4500 rpm, but 4500 to 9500 look out. Although not a daily driver, It did last 12 years on the street.

The Money Pit

I tend to be a "bottom of the list" cam guy,and when I picked the Isky,I knew I was getting close to crossing the line with street manners.Never occurred to me how close it was to the L-88.

So 13-14mpg is good from what I'm hearing. I ran into a guy at Carlisle running a 350 with a dual quad setup that claimed 9mpg,and I at the time was running a dual plane and smaller hydraulic cam,and was getting 15.5 mpg then.That's nice concidering the 50 extra cubes,and around a hundred extra horse power.

I would be interested to hear from the 427 guys what kind of mileage they're getting.An no,this is not a real concern,just curious.I run 3.70 gears and in second on dry roads can slide the back around if I hit the throttle too hard.Isn't that what Vettes are supposed to do?

aaronz28

i've driven Walts L88 on the street... and it is way more streetable (with headers, c/r 4speed, and 4.10s) than either my Z28 or L84.

The only "unstreetable" part of that motor (aside from the fuel consumption) is how fast it overcomes the chassis and burns the tires right off the car.

Of course i'm used to a stock 69Z28 with its original 30-30 cammed 302 and my 64 FI..

If you can run the fuel, i'd build a clone spec l88 anyday..

in fact, thats my next plan LOL

A

jkuzzy

Absolutely love those pictures!

67pete

I ran mine for 3 years on the street...what a blast! You'll need 4:11's at minimum, if it's around town, you'll also need a VERY good cooling system ( I also used a product called '40 Below' (I believe) ) ..come to think of it, it really wasn't that bad out on the GSP at speed

DansYellow66

My car has what I call a pieced together L-88 and it's not that bad. It has 69 open chamber aluminum heads and a 68 L-88 intake, Cam Dynamics 22870 mechanical cam - .600 lift, Ross 12.0 pistons and the big rods, etc.. I do run a 427/425 carb, vacuum distributor and fan shroud which no doubt help. With a M-20 and 4.11:1 rear its very driveable - if not exactly quiet. Mileage is in the aforementioned 7-8 mpg range however.

Dan

The Money Pit

I run a Griffen 31x19 aluminum radiator and MSD ProBillet HEI with the vacuum advance can,so cooling is not a problem.As for quiet...the wife can hear me coming a block from the house.

DansYellow66

Reportedly a stock L-88 with cast exhaust manifolds would not pull nearly this much HP - maybe 450 as a guess. With headers and proper tuning they were suppose to be in the 550 HP range.

I'm sold on vacuum advance distributors. Just getting a proper vacuum can that would work with 8 inch vacuum at idle and hooking it up to full vacuum source made my car run nice and cool.

Dan

Ironcross

I dont use a vacuum advance for a couole of reasons.

1, The vacuum advance canis plugged and none used with
L88`s.

2, As soon as you step on the loud pedal your way past
3 G`s on your way to well over 7 G`s anyway.

C64BOB

The L-88 cam is a nice street grind. Torque everywhere (too much for an unflared car). Takes a little tuning to get the driveability good. Pretty much like a 140 in a 350. Tripower and the L-88 cam will get 13-14 mpg when sorted (if you can keep your foot out), 9-10 mpg maybe with a 4 barrel. Like all the Chevy cams it doesn't need too much spring and doesn't beat the valve train up.

glenn64vette

I worked with a guy, way back in 71, that had a 67 L88. He drove it everyday to work --- a SHELL STATION. I actually raced him one night with my 64 Hipo 289 Fairlane --- boy did I kick azz--- lost by 20 car lenghts


Now, that I think about it, I got my 64 13 months later..

63 340HP

When we upgraded the L72 we stuffed into a 68' SS396 Camaro to closed chamber head L88 specs (12.5:1 pistons and the cam & springs) we found the same thing, we lost the low end torque. We had to swap the 12-bolt 4.56 gears for 4.88's, and then to a 9-inch with 5.57's and back to 5.13's (31-inch tire). It took a while to tune the combination. We ended up with a complete rebuild of the drivetrain and suspension (we broke everything), and an 8-inch converter (to overcome the off-idle to 4000 rpm performance), along with a swap to a 1050 Dominator on one of the dual-plane C454 Edelbrock manifolds (to restore some of the low rpm torque). We drove it on the street, but I would not call the final result very street friendly. It was fun (if 8200 rpm and 136 mph through the traps is considered fun). Mileage?

The original poster's 406 with the Z-35 is probably a good combination. The Z-35 is fairly close to 30-30 specs with tighter lobe centers and slightly more lift (good for the extra displacement and better intake & heads, compared to an L76 327). I would not consider the combination a SBC L88, but it should plant @ 375 RWhp (respectible hp).