Very happy with LT4 topend conversion kit
Thread Starter
Registered User
Joined: May 2003
Posts: 184
From: 6500 MSL
Very happy with LT4 topend conversion kit
Hi,
I received my topend LT4 kit from gmpartsdirect just two days ago and must say that I'm very happy with it appearance wise so far and with their service. $2200 and everything was packed very well and came quickly and aside from some dust on the intake (been sittin' on the shelf a while I guess) everything looks brand spankin' new (I guess because they are... :-P) It's weird but I just love the smell and feel of new auto parts
. Must be something in the oil.
The cylinder head castings appear to be top-notch and after reading the David Vizard book I feel I'm ready to start pocket porting them. That's supposed to add around 20 hp if you do it right.
I know a lot of guys on here probably get more horsepower for the money with Stage 27 AFR heads and an XE 920/986 cam
, but just to let hesitant buyers know, I feel really good about having made this purchase. I'm a GM OEM parts-addict type, so I'll feel really good once this is installed in Star Dragon, as it is both aftermarket and GM at the same time
.
Any other GM lovers/OEM neurosis folks out there?
I received my topend LT4 kit from gmpartsdirect just two days ago and must say that I'm very happy with it appearance wise so far and with their service. $2200 and everything was packed very well and came quickly and aside from some dust on the intake (been sittin' on the shelf a while I guess) everything looks brand spankin' new (I guess because they are... :-P) It's weird but I just love the smell and feel of new auto parts
. Must be something in the oil. The cylinder head castings appear to be top-notch and after reading the David Vizard book I feel I'm ready to start pocket porting them. That's supposed to add around 20 hp if you do it right.
I know a lot of guys on here probably get more horsepower for the money with Stage 27 AFR heads and an XE 920/986 cam
, but just to let hesitant buyers know, I feel really good about having made this purchase. I'm a GM OEM parts-addict type, so I'll feel really good once this is installed in Star Dragon, as it is both aftermarket and GM at the same time . Any other GM lovers/OEM neurosis folks out there?
Last edited by Kuma; May 24, 2003 at 08:28 PM.
SWEET!!!!!!!!!!!! I have a feeling yuo are soon going to feel true love when it is all togeter!!!
Registered User
Joined: Oct 2002
Posts: 856
From: Denver
Re: Re: Very happy with LT4 topend conversion kit
Originally posted by simple
nope, since they screwed us enuf on the opti and rearends J/K
nope, since they screwed us enuf on the opti and rearends
J/K
You should be able to play with the ls1s.
Registered User
Joined: Sep 1999
Posts: 506
From: Boulder, CO. USA
If you're planning on porting the heads yourself, here's some good reading...
http://www.sa-motorsports.com/diyport.htm
http://www.sa-motorsports.com/diyport.htm
Registered User
Joined: Jan 2002
Posts: 955
Originally posted by Followme
xxsaint69x
Where can the lt4 hot cam kit be bought for 450?
xxsaint69x
Where can the lt4 hot cam kit be bought for 450?
Registered User
Joined: Aug 2002
Posts: 1,509
From: Red Oak Texas
Kuma-
I am sure that you wil be happy with the heads/cam set up. The bowl area's are pretty large on the LT4's from the factory. Some need minor blending to the seats but the bowl is large and kinda weird shaped and doesn't really get shaped correct unless you go to larger valves. If you just narrow the guide boss, that should be all that is required.
Followme-
I think you can find Hot Cam kits for "about" $480-500. Most people chose this cam and kit b/c of price and "bang for the buck" but I would suggest spending another $100 or so and get a Comp XE cam (218-224, 224-230, 230-236, etc) and kit from CombinationMotorsports. There is nothing bad about the hotcam but most people would rather have one of the XE grinds but they expect to pay ALOT more and at this price, you get a better cam, better springs, retainers, locks, 1.6 roller rockers (SA or NSA) and guide plates if needed.
NightTrain66
I am sure that you wil be happy with the heads/cam set up. The bowl area's are pretty large on the LT4's from the factory. Some need minor blending to the seats but the bowl is large and kinda weird shaped and doesn't really get shaped correct unless you go to larger valves. If you just narrow the guide boss, that should be all that is required.
Followme-
I think you can find Hot Cam kits for "about" $480-500. Most people chose this cam and kit b/c of price and "bang for the buck" but I would suggest spending another $100 or so and get a Comp XE cam (218-224, 224-230, 230-236, etc) and kit from CombinationMotorsports. There is nothing bad about the hotcam but most people would rather have one of the XE grinds but they expect to pay ALOT more and at this price, you get a better cam, better springs, retainers, locks, 1.6 roller rockers (SA or NSA) and guide plates if needed.
NightTrain66
Thread Starter
Registered User
Joined: May 2003
Posts: 184
From: 6500 MSL
nighttrain,
I've read through the SA porting guide and one thing I don't understand, but that they seem to emphasize, is gasket matching the intake ports. I recently read the David Vizard book on porting and he says that one actually shouldn't enlarge to the size of the gasket because these areas are not really that restrictive to begin with, and that one should emphasize the bowl work and valve guide bosses, short side radius etc. Also he says that you should use the gasket as a reference, but not actually enlarge the ports to meet the gasket (but rather establish some smaller circumference to enlarge them to, using the gasket as a template). What do you think?
Thanks.
I've read through the SA porting guide and one thing I don't understand, but that they seem to emphasize, is gasket matching the intake ports. I recently read the David Vizard book on porting and he says that one actually shouldn't enlarge to the size of the gasket because these areas are not really that restrictive to begin with, and that one should emphasize the bowl work and valve guide bosses, short side radius etc. Also he says that you should use the gasket as a reference, but not actually enlarge the ports to meet the gasket (but rather establish some smaller circumference to enlarge them to, using the gasket as a template). What do you think?
Thanks.
Registered User
Joined: Aug 1999
Posts: 50
From: South Bend, IN
I picked up full second and about 8 MPH with Hot LT4 conversion electric water pump, longtubes and a custom program. Very happy with it for the money. Picked up another 8 MPH with 4.5lbs of boost.
Registered User
Joined: Aug 2002
Posts: 1,509
From: Red Oak Texas
This is MY opinion, Some might agree, some might not.
The gasket matching does NOTHING. Once the opening is as large as the pushrod pinch. you are just adding un wanted runner volume (in a bad place) and the making the air turn more before going around pushrod pinch. If you can raise the roof at the gasket flange and the injector is not in the way, that will help you.
If they were LT1 castings I would say "take a back hoe to them" and widen the pushrod walls and enlarge the bowls as much as possible but the LT4 has a lot larger runner in stock form and I would suggest just narrowing the guide boss and using some Impala head gaskets with that cam. If you were using a XE 230-236, 236-242, GM 847 cam and were wanting to turn 6800 RPM AND NOT WORRY ABOUT POWER BELOW 3000 RPM, I would say they need to be "fully ported" as well but for the Hot Cam and power from 2000-6200 RPM, they are fine in stock form.
Once again, these are MY opinions.
NightTrain66@msn.com
The gasket matching does NOTHING. Once the opening is as large as the pushrod pinch. you are just adding un wanted runner volume (in a bad place) and the making the air turn more before going around pushrod pinch. If you can raise the roof at the gasket flange and the injector is not in the way, that will help you.
If they were LT1 castings I would say "take a back hoe to them" and widen the pushrod walls and enlarge the bowls as much as possible but the LT4 has a lot larger runner in stock form and I would suggest just narrowing the guide boss and using some Impala head gaskets with that cam. If you were using a XE 230-236, 236-242, GM 847 cam and were wanting to turn 6800 RPM AND NOT WORRY ABOUT POWER BELOW 3000 RPM, I would say they need to be "fully ported" as well but for the Hot Cam and power from 2000-6200 RPM, they are fine in stock form.
Once again, these are MY opinions.
NightTrain66@msn.com