LS1 98 Heads
LS1 98 Heads I have a set of 98 heads and hear they are junk. Are they were porting and setting up, or are there issues with velocity? I know the 243 heads are better, but will these heads work good with a port job and some springs?
Staging Lane
Joined: Apr 2004
Posts: 68
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From: Houston, TX
I still have the stock heads on my cammed LS1. The only real difference between the heads for 97, 98 and the later LS1 heads was the use of perimeter bolt valve covers.
See my sig on how the cam, ud pulley, air filter and tune did!
See my sig on how the cam, ud pulley, air filter and tune did!
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Originally Posted by gonbad
The only real difference between the heads for 97, 98 and the later LS1 heads was the use of perimeter bolt valve covers.
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Verdad Gallardo I have a '98 motor that I'm going carb with and was deciding how to deal with those heads. I'm using them regardless for now, but wanted to see if anyone had them ported and how they did. Thanks for the info. guys.
Originally Posted by STL2SLO
Anyone have any good results in porting a set of 806 98' heads? If so, I would like to see them...
Staging Lane
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From: Arizona Two blocks north of Hell
I made 394/365 cam only & bolt ons with these heads untouched. Correct me if I'm wrong but isn't there also an area on the deck side that needs to use graphite gaskets to seal good?
It's already been noted, but perimeter bolt pattern is different. There has been much talk about them. The short turn radius on them is where the difference in flow comes. Every dyno is different, every flowbench is different, every track is different. It's hard to get a comparo from everyone else's numbers. I am not a head porter but have done my own 98 heads. After I ported my heads, I got them milled. The stone on the milling machine broke on a head and the machinist ordered another head and milled it before he informed me on what he did. After he realized the mistake he corrected it and got the right head. He let me keep the 99 head and I used it to make a few comparisons. These numbers are from memory. This was a few years back but pretty close. 98 heads on this bench were 224 stock, 253 ported by me. 99 head was about 230 stock and 255 ported by me. Like I said, I am no pro, this was my first and only attempt at porting heads but all of the ports on the 98 heads flowed within 3 cfm of each other so they were faily consistant. The stock flow numbers seemed very low to me and the ported numbers seemed just a little higher than I expected from the stock heads, however, if you look at the difference between the ported and stock heads. I picked up about 29 cfm on the 98's and about 25 on the newer heads. I'd say that with the right porter, 98 heads will flow about the same as newer heads but I believe the intake runner will be a little bigger having to cut more out of the floor on the short turn. Hope this helps a little.
well, i'm stuck with them for now too. instead of porting them, i would recommend finding 243's to port and just holding on to them. Moneys is better this way, atleast better than paying for AFR's
Originally Posted by mypoorLS1
It's already been noted, but perimeter bolt pattern is different. There has been much talk about them. The short turn radius on them is where the difference in flow comes. Every dyno is different, every flowbench is different, every track is different. It's hard to get a comparo from everyone else's numbers. I am not a head porter but have done my own 98 heads. After I ported my heads, I got them milled. The stone on the milling machine broke on a head and the machinist ordered another head and milled it before he informed me on what he did. After he realized the mistake he corrected it and got the right head. He let me keep the 99 head and I used it to make a few comparisons. These numbers are from memory. This was a few years back but pretty close. 98 heads on this bench were 224 stock, 253 ported by me. 99 head was about 230 stock and 255 ported by me. Like I said, I am no pro, this was my first and only attempt at porting heads but all of the ports on the 98 heads flowed within 3 cfm of each other so they were faily consistant. The stock flow numbers seemed very low to me and the ported numbers seemed just a little higher than I expected from the stock heads, however, if you look at the difference between the ported and stock heads. I picked up about 29 cfm on the 98's and about 25 on the newer heads. I'd say that with the right porter, 98 heads will flow about the same as newer heads but I believe the intake runner will be a little bigger having to cut more out of the floor on the short turn. Hope this helps a little.
