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Discussion Starter · #1 ·
I am getting close to building my 396. I just got an L88 intake and when I set it on the heads/ block, etc. There are a couple of ports in the heads that aren't covered by the intake. The intake decodes as an L88 and the heads are 380 L88's. What am I missing?



Thanks for any help...
 

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The intake manofold gaskets blocked of these ports on my 396.
 

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Those are open with most big block manifolds. Their function is to cool the exhaust crossover and collect crud. The lower ones are also part of an air pocket under the crossover which helps keep oil from heating and getting burnt there.

Good Luck!
 

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My felpro gasket set only blocked of the top of the hole that is visable in your picture when the intake manfold is set in place.
 

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Discussion Starter · #6 ·
They don't go anywhere so don't worry about them. I would think twice maybe three times about using a gutted plentium(spelling) manifold on anything especially a 396.
Thanks for the info.... everyone. I'm a little new to BBC's and engine building. This intake was used on a few 67 Corvette 427's. The plenum was actually left off the casting rather than removed. It's a fairly rare piece. This was supposed to increase high rev HP. Or that's my understanding. I would much prefer low end torque to higher revs. Because the date code is perfect for my build, I wanted to use it but I may need to reconsider. What is your reservation with the 396?
 

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Not enough cubes. The motor is a holly terror above 4500 RPM but a dog below that. The L-88 had additional cubes and a lot more compression with a very radical (for it's day) flat tappet cam.

On the street with a small cube BBC (many SBC are bigger and lighter on the nose than you are) you will need as much bottom end torque as you can get.

The L-88 was an over the counter early style crate motor sold to racers who wanted to win drag races by throwing away their 396 cid 375 horse engine and keeping only the valve covers and air cleaner. It had 12.5:1 pop up pistons the heads and intake you have and the L-88 solid lifter cam which had a lot of lift and a narrower than stock LSA. It looked like a 396 but put out over 600 horse power in it's power band of 5,600 to 7,800 RPM. Most folks don't run that kind of RPM on the street for fear of being arrested.

For street driving most folks throw a longer arm into a 454 and get all the torque and horse power that they can possibly use out of 496 with oval port heads. For the street you want the smaller oval port heads to build low end to middle range RPM’s (still will run up to 6,200 RPM with oval ports before they fall over with a 454).


Larger Dave
 

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That depends on the block. With no core shift, people have bored them to 4.25. Unless you want the block with a particular casting # you'd be better off finding a 454 block.

Good Luck!
 

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The manifold has no bottom end power and really runs terrible at normal street driving RPM. It was the first attempt at a true race manifold for the BB and didn't really work. Look around for an uncut dual plane they are the best street manifold there is.
 

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The manifold has no bottom end power and really runs terrible at normal street driving RPM. It was the first attempt at a true race manifold for the BB and didn't really work. Look around for an uncut dual plane they are the best street manifold there is.
In fact, it was so bad they had to use a special Holley 850 with stagger jetting and a tab to direct flow in one of the secondaries. I sold the one I had like a hot potato.

BTW, I don't think the manifold was cast like that, it looks more like it was broken out. Mine and the ones I've seen pix of were machined.

Good Luck!
 

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An L-88 manifold and heads should only be run by someone wanting a numbers matching stock appearing motor for some class or white glove car show. There are better heads and much better manifolds for the 396. The factory manifold was machined out with a vertical mill and the carbs were indeed staggered jetted to compensate for the good passage/bad passage of the L-88 head (the long dog leg one is the good passage and the short straight one is the bad in terms of flow numbers and fuel distribution).

Do not forget that the cylinder walls severely shroud the intake valves with a 396 so a good manifold is critical to building power. You can not bore out a 396 safely to 4.25" unless you have a rare 1965-1966 block that still was cast with the thick cylinder walls that ultimately became a 427 (the factory initially wanted to replicate the bore and stroke of the 409 so the early blocks have really thick cylinder walls to accept a big over bore).


Larger Dave
 

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Wow! Good history lessons here. I'm reliving my youth vicariously.
But my engine isn't. Torquer2 since 1970. I called Edelbrock a few weeks ago. Said I wanted the latest and greatest intake to replace it. They said "We sell the latest and greatest,,,but not better than that! You have a great manifold!" I kept it. See how the throttle body is turned to starboard?
 

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Discussion Starter · #15 ·
Wow! Good history lessons here. I'm reliving my youth vicariously.
But my engine isn't. Torquer2 since 1970. I called Edelbrock a few weeks ago. Said I wanted the latest and greatest intake to replace it. They said "We sell the latest and greatest,,,but not better than that! You have a great manifold!" I kept it. See how the throttle body is turned to starboard?
Thanks for the reply. Is your engine a 396 or 427? L88 heads?
 

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Ah, the old 409 "W" engine..

If only we could get Mark IV blocks that came stock w/ a 4.3125" bore like the 409 and that then could be bored out another .125"....

Close to a 4.44" bore or so.............

Add one 4.375" crank and make an about 542" engine..

He, He!!

pdq67
 

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Dreamer! But hey, I had a 348 tri power (350 Horse(yeah, right!)) in my 61 bubble top. Tried to build a 409. Even have an old cam laying around that I was going to use. But when I could score a nearly new 396 from a wrecked 360 horse SS Chevelle, I went the easy way.
And that reminds me of a story. he he
It's 1967 at the drags at Pyallup Raceway. The national record holder in A/S was there running his new L88 black Corvette. (He was in the low 11's)
Anyway, he was just a kid like me. My search for 409 parts led me to his service shop and I bought the cam from him. Nice guy. BUT! He gave me a ride in his Corvette. It's a ride that I've never had before or since! We went up the river-road (Pyallup is also a river) to a long straight-away. No traffic in those days. He stagged and dumped the clutch. (Uniroyal redline E 78's) Of course they went up in smoke. He hit second. I turned and looked over my shoulder. Solid smoke as if he was doing a burnout but we were doing 50. He hit 3rd. Same thing. He hit fourth. SAME THING. Solid smoke. After about 3-4 seconds in fourth he backed off and the smoke started to lessen. I looked at the speedometer: 110. We went back to the shop and he parked it. I bought the 409 cam for $10.00, thanked him and left. I was dazed.
The next year I bought my L88. When the Camaro was delivered with the 396 375hp, I still had my 396 bubble top so that meant that I had three Rats at the same time. Not bad for a poor kid, during war time, in '69.
If I only new then, what I know now. OK, no more clichés.
 
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