chief455

iTrader: (21)

can sombody link me to threads about lt4 intakes, edelbrock lt4 intakes vs lt1?

I have a 383 lt1, stock lt4 heads with a cam, headers, 3800 stall and 4.10's
still a stock lt1 intake though
got a 52mm tb and nice MAF - what should I do to get the most from the heads/cm/headers?

1bdbrd

iTrader: (12)

Port your heads first and foremost. You can cram all the air you can through the intake but if it gets stopped up at the heads you aren't really going to make justifiable gains vs. cost. Get the heads ported and the intake ported as well. With that alone you should see some very nice gains.

Now as far as the intake itself, I would personally start with the Edelbrock LT4 intake to match your heads as its much cheaper than a real LT4 intake.

chief455

iTrader: (21)

oh - porting/swapping the heads may come later - I'll go about it then
not an option now as the car is together and fairly fresh

for now - just what intake will compliment my stock lt4 heads, 230/230@.050 ish cam, longtubes, 3800 stall and 4.10's?

is the LE ported lt1 a cost effective upgrade over stock lt1?

I have #30 injectors and adj regulator too
bought the car this way - trying to get it matched better up for now
thanks

1bdbrd

iTrader: (12)

Honestly, I would wait and upgrade it all at the same time and have a matched top end. Then you also won't be doing the same job more than once. But honestly if you already have LT4 heads then I would get a ported LT4 intake.

chief455

iTrader: (21)

See - you're undecided too!

So - like my gut - your thinking toss an Edelbrock on it for now - won't hurt/might help. Then with more porting/aftermarket heads later, also port match the intake. Sound reasonable?

I've already concluded from reading that I will need to pull my intake and measure the port openings since so many gaskets are out there.
I've passed up one ported LT4 intake already because it has way too large oenings to match my stock heads. Need one I can use now - port to better heads later.
It may be over a year before I'm pulling the heads..
I wish I could find the dimensions of stock LT1, LT4 and Edlbrock LT4 openings...

GIZMO

iTrader: (8)

I can't help you on the Edelbrock intake, but here is a photo of all four versions of the LTX factory intakes. The LT4 is on the bottom. All four have the same height opening and same width on the bottom. Both the 1997 LT1 and the LT4 have ports that match the LT1 head opening. The LT4 intake has more material above the injectors to seal against the larger port openings in the LT4 heads. Use gasket GM part number 12367777. It will not cover part of the opening like the production LT4 gaskets do. Don't worry about porting for now. The production LT4 heads/intake will support a bunch of HP as-is.

Good Luck,

Daren

http://s85.photobucket.com/albums/k5...t=DCP_1455.jpg

chief455

iTrader: (21)

GIZMO (Daren) -
Now that's a reply!
Any chance you know the port opening differences between stock LT1, LT4 heads - by dimension?
I ask so I'd be aware if a "ported" intake is for sale, the port size would exceed the size of my stock LT4 heads. Also as information about how much guys like AFR - that give their dimensions - are opening the heads up.

Do you think my cammed 383 with LT4 heads and LT1 intake will feel better with an LT4 intake swap?
Port opening the same - but said to be angled, distanced differently.

BTW - back a pic in your album clearly shows the extra material mentioned on the LT4 manifold for those reading this. Plus some nice parts and cars

GIZMO

iTrader: (8)

The port opening on an LT1 casting (10207643) is approx. 1 1/16" wide top, 1 1/8" wide bottom, and 2" tall. Note that there is a slight difference port to port on the same head. The LT4 opening is approx. 1 1/8" wide top to bottom and 2 1/8" tall.

GIZMO

iTrader: (8)

If you are running an un-modified LT1 intake on LT4 heads I am surprised that you don't have a pretty good vacuum leak. The LT1 intake gasket hangs into the LT4 port quite a bit. The LT4 intake will allow you to run the LT4 gasket which should seal better. The 1997 LT1 intake and the LT4 intake are identical except for the extra material. The only only port difference in all of the intakes is at the opening. I would suggest that the Edelbrock intake would be a better choice than the factory LT4 intake.

chief455

iTrader: (21)

Did you mean 1-1/16" top ~ 1-1/8" wide botom, 2" tall LT1 port
1-1/8" wide, 2-1/8" tall LT4 port?

As for the rest - good data.
I guess I'll start with the Edelbrock intake and GM LT4 gaskets with a 52mm tb for now.
Should be improved over the LT1 and stock tb.

Then I can upgrade intake and heads later.

Thanks for all the help!
Geoff

T/A KID

iTrader: (12)

I will have my LE Ported Edelbrock LT4 intake By Tuesday. Opened for a Monoblade with all the work he does on them, from his own words the stock Edelbrock is about as good as his Fully ported intake. So Good Things can come from a Ported Edelbrock.

chief455

iTrader: (21)

good to hear - what did the porting run you? hoow long? will you be able to give us before and after results?

T/A KID

iTrader: (12)

Porting was $200, I'd say roughly 3 weeks depending on if he can get to it when you send it. Before and after will not be valid on my car, going from a Bolt-on LT1 to a VRE 383, LE3 AFR's, custom Grind cam, D1SC air-air setup, with a 4L80E tranny and all the little things in between, lol.
From what Lloyd told me the runners are longer than the factory castings, but there is less plenum volume. However with a Bigger TB like my monoblade you'll get it back. Also there is alot of material that can be taken out especially right behind the TB.

chief455

iTrader: (21)

T/A KID - thanks! Your set up sounds sweet - good luck