I have a 76 L82...doing a straight overhaul...trick flow DHC 175 heads..new L79 or L82 cam..wanting to use a Mercury marine cast iron intake..14096242 code..said to be same as Lt1-Z28 aluminum..heavy but cool

 

Did you check hood clearance?

 

I got one of those for free. It was cracked under the front coolant passage, repaired with a bunch of epoxy, which had failed and was leaking badly. I only realized this after wasting a bunch of time cleaning it for use.

Don't bother. Especially if you already have aluminum heads.

 

Not sure what makes it cool. But, whatever floats your boat.

 

It's a tall manifold. The circle track racers used them because of the rules. An LT-1 drop base air cleaner might work to fit under your hood.

You might consider the bow tie aluminum ZZ-4 intake. It's shorter in height and makes as much power as the LT-1 manifold.

10185063 is the casting number. It fits under my '80 hood with the stock air cleaner and cold air intake.

 

THIS ZZ4 Chevy Bowtie manifold^^^^!!!

One of the best manifolds out there, making more power than most of the "preferred" aluminum manifolds that are often cited for the SBC Gen 1 engine for a performance intake. Not only does it generally make the most power/TQ for an aftermarket manifold that will fit under the C3 hood, the same if not more HP than the infamous LT-1 manifold, but also looks more OEM with the Chevy bowtie symbol embossed in the aluminum. If I was going aftermarket intake, 100% all day would pick this intake for my L-82.....

 

How does the ZZ4 intake compare to the / a stock Q'jet intake for height ?
Anyone have EXACT carb pad height measurement or comparison ?
Thank you,
Jerry

 

Yes I do. Basically, the ZZ-4 is a half inch taller.


Stock GM L-82 aluminum intake measurements taken front and back from china wall surfaces to carb pad.

ZZ-4 GM Performance Parts aluminum intake. Measurements taken from china wall surfaces to carb pad height straight edge.

 

This cast iron intake i am going to use just to try if nothing else just to see what happens..it is 4 inchs from china wall to carb pad at the front and 5 3/8 at the rear..i play around with scca and corvette autocrosses and i am usually in class by my self (exhibition class) with aftermarket intake...i figure the new aluminum heads will offset the weight of the intake..besides i just gotta be different..worry about hood later!!

 

Thank you Mark - much appreciated.
I can't accomodate a 1/2" increase in height on my '59 without undoing some other modifications : a 5/8" spacer under my drop base hi-po air cleaner.
I already dropped my engine to accomodate the air cleaner.
The other thing is the ZZ4 intake probably has larger runners then my intake same as yours - L82 1978 I believe and mine has heat barrier coating applied and old school oil tube / breather pipe installed.
My engine is lo-po 300 hp327 (stock cam) but well tuned
Jerry

 

Jerry,
Why do you need the 5/8" spacer? You could take that off and gain 1/8" better than you have now?
Is it about fitting a double pumper?

 

The air cleaner spacer straightens and guides the air flow going into the carb (Q'jet) - there is PROVEN benefit to doing this : I believe dyno testing has shown ~ 5hp.
Somewhere on the forum this was discussed and results posted - I did it MANY MANY years ago before the forum ever existed
I attached the spacer to my air clnr and molded a nice radius going down to the base of the air cleaner getting rid of the lip adjacent to the carb

I have done work inside my intake to aid flow , and also had it coated with heat barrier , and had welded a piece of aluminum underneath so I could machine the intake to put in an oil filler tube at the front.
This is probably the only EGR intake you will ever find like the one you have with an oil filler tube installed
This is a lot of work that I don't need to repeat at my age
If I had FA better to do I might consider changing intakes but the only reason would be to see if I could improve my 1/4 mile performance.
For street driving and throttle response there may be nothing to be gained except unneeded work
I will (probably) never race the car again as I have other things I still want to do.

The ZZ4 intake I'm sure would flow better at higher RPM but would probably give up some torque in the low end.
Our Q'jet intakes were good enough for GM to use on the '68 - '69 350 hp cars so they can't be to bad ?

Your photo's show both intakes (your and my stock aluminum) and the ZZ4 - any thoughts on doing a dyno comparison - now THAT would be VERY INTERESTING

 

Nobody wants to test a stock intake against anything aftermarket. The guys that were at Edelbrock back when they were developing the "Performer" say that you will get LESS efficiency (gas mileage) with the Edelbrock intake and not much power over the cast iron L48 intake. That casting has been revised a few times so who knows now. I still believe you can get good results from modifying the stock intakes. David Vizard did a good bunch of work on one and it really helps.

Nobody wants to know.

 

You just need to bondo up the front for looks where the brass water passage insert mates with the cast iron and paint it aluminum LOL

 

Good to know. I'll save the money and keep my stock L82 intake.

 

Exactly what I did with my stock L-82 aluminum intake because I wanted to keep the OEM L-82 as original as possible with the exception of the AFR cylinder heads.

The expert builder who did the machine work and the bottom end build on my engine only for me, at my request voluteered to clean up the L-82 intake and mildly ported/selectively smoothed the rough surfaces insides for superior airflow over the factory machining. We discussed the aftermarket intakes and his guidance to me was with my mildly ported aluminum intake for a sub 6,000 RPM street engine, the differential versus aftermarket intake would be VERY minor.

With all that said, IF I was going to an aftermarket intake, hands down as mentioned earlier, the reason I suggest the ZZ4 intake is that in the comparisons I have researched over the years, it almost always comes out on top versus all the aftermarket low rise intakes that will fit under a C3 head. The comparisons are out there on google........

 

I like to build the power where it makes the most sense and let the little things go. The current build has optimized idle to 6000 power band and it does not nose over at the top. Super nice 383 driver with plenty of torque right off idle. The stock intake would (did) work well as-is but even better when massaged a bit. I didn't "need" to change it but I found a nice ZZ4 intake when it was apart, so I swapped.

The ZZ4 helps at the top end but gives nothing back at the bottom end.

 

I KNOW someone who tested ALL the original GM 1960's and up lo-po intakes and the EGR intakes were the best flowing low rise GM intakes made
I believe the EGR feed passage hole in the divider helps higher rpm capabilty - similar to cutting down or removing dividers.
And using the "open" thick insulator base gasket really adds to the cut down divider effect.

IN CASE SOMEONE WANTS TO KNOW !

 

Hmm I have seen and read many different independent dyno comparisions of stock vs different aftermarket intakes. While I agree the gains are typically smaller than say replacing a mechanical radiator fan with electric (which is low fruit for some reason many folks feel isnt worth it), they are still gains. and there are things such as a cutout in the center divider or using a 1/2-1" open spacer which almost always give you more top end. In fact the comparisons Ive seen between the performer rpm and performer rpm air gap show the performance is identical once you cut the same divider in the older rpm design that doesn't already have it.
Different intakes suit different combos better... If your bolting an air gap onto a stock l48 dont expect much. but if the engine can make use of the additional flow like the OP with aftermarket heads and (hopefully) a better flowing exhaust then you can expect to see average gains in the 7-11hp range with just the intake vs a stock intake (depending on stock intake)

The heads on a stock c3 are the largest single inhibitor to power.

 

The 2101 Performer IS the ZZ4 intake....I have compared the two on a bench and they are almost identical.

Putting a Cast Iron intake on a pair of TF DH175 heads is a step backward....the shape and design is a good one but the SOB weighs 50 lbs. and it holds a lot of heat in.....

You can unbolt a stock Q-Jet intake off of a Goodwrench 350, bolt on a 2101 Performer and watch it pickup 12hp right off the bat....has been done and tested a thousand times....and the more power you make, the more it will pickup.....
The 68' L-79 327 was rated at 325hp....where do you think the power loss came from? Going from high rise aluminum intake to a low rise cast iron....

The low rise intake is a pretty good piece for what it is but has been outclassed by time and tech.....

The original performer was a waste of money....all the intake companies made stockish aluminum repops back then and sold them as "performance".....

Jebby