Marc 85Z28

300cfm from a stock SBC iron head? Got proof?

And if he got anywhere near 300cfm: At what lift? What was the resulting port size? Low lift flow numbers?

95redvert

I am assuming that when you speak of the 083 heads, that you are talking about the stock cast iron heads of a L98 right?? If so then I say go for it. Three years ago I took my stock heads off my L98 because she needed new valve stems. While they were off I had the 3 angle valve job, plained .20, and ported the bowls. All said and done I spent about $200 and dropped exactly 5 tenths off my 1/4 mile time. I went from a 14.8 in the summer of 2001 to a 14.3 in 2002. Not bad for $200 and no intake or exhaust porting. I think I would have easily dipped into the 13's had I spent some quality time on the intake and exhaust ports.

wyclefsirocz

somethingg was wrong if you running a 14.8 w/ a 350.

f-bodybuilder

I'd say that's pretty good, considering I've yet to see a stock GTA run anything lower than a 15.

wyclefsirocz

i dunno aboput GTA's, but a kid on one of the local boards around me ran a 14.69 stock exepct for a set of K+N filter and bosh +4 plugs, he also was running a ttop car that weighed in around 3570 race weight. he got a set of headman LT's and a flowmaster Catback, w/ an air foil. ran a 14.3, went with a set of SLP runners and a set of 3.42 gears and ran a 13.9
then his tranny went, rebuilt it w/ vette servo transgo shif kit and a 2000stall converter. at the same time he put in a LS1 drive shaft. and some new nitto 555's

ran a 13.76

w/ an dMSd now and the LT4 cam he now runs a 13.30 w/ a new tune

wyclefsirocz

BTw this on a a set of stock heads, he is going with a set of ,lighty ported and polished set of vette heads, so bring up the compression and to flow a lil better w/ a new tune and some new KB pistons. alsong with a better manifold, pored to matc heads. he is hoping for a 12.90 pass.

but we will see.

97WS6SCharged

My L98 is being punched out to 383 cubes with a set of Dart Pro 1 215CC heads and a Stealth Ram. Of course it's going into a truck that weighs under 3000 lbs so it should move pretty well. And if it doesn't, I've got a 150 shot waiting.

95redvert

There was nothing wrong with my motor or car. That is what 99% of stock '87 - '90 L98 powered cars run.

f-bodybuilder

We're getting away from my original question! I need the dumbed down explanation of what makes 083 L98 heads' 64CC chambers different from it's brother's 76CC chambers. Maybe some visible difference?

FruityOne

L98's came with one of two head choices. Early L98 Vettes, and all F-bodies received the iron 083 heads. While later vettes (86+ to pre-Lt1) got the aluminum 113 heads.

L98 iron heads are 64cc from factory.
L98 alu. heads are 58cc from factory.

TBI 350 (Casting #193) heads are 76cc or 64cc, but have the dreaded "swirl port" runners. Great torque, but NO flow after 4,000rpm they die a quick death.

Proof of massive gains from some major port work on L98's below.
------ http://www.thirdgen.org/techbb2/show...hreadid=183264

.1 82.5 52.5
.2 145.6 111.8
.3 212.9 150.1
.4 245.4 178.6
.5 269.2 190.9
.6 270.6 195.2

With a full competition port he gained another 25cfm I'm told. So yeah. if you got the time and money L98's can be worked over pretty good. I wonder what #'s Lingenfelter gets out of their CNC port jobs.

Marc 85Z28

Impressive numbers! But after reading what he's done, what it took to get there in both cost and time, I still think it was foolish. I'll bet the heads are so thin they'll crack the first time they see duty. I wonder what kind of real numbers he put up. Not CFMs on the heads, but numbers on the big screen at the end of the track

FruityOne

Ask and you shall receive!

Stock L98 camshaft, with ported heads and all bolt ons 350hp at the wheels. Sounds pretty good to me!

Yes, he mentioned several times through all 4 articles, but he did it so he could right the article step by step. Thats why he went to such an extreme on the porting.

Me? I'd just buy a set of protopline Iron Lightning's with 2.02 and 1.6 valves and call it a day. Aluminum would be nice, but I don't need to spend that much. Plus, with porting you could go MUCH further.

IZ28

Not the G92 Camaros. The 2.77/2.73 cars usually run around those times.

Dyosis

Mine should get respect once I throw on my AFR 195 heads, a Holley stealthram, some headers and a cam

With a good tune I should be somewhere in the low to mid 12's hopefully (crosses fingers). I shouldn't have much trouble showing the stock/mildly modded LS1's what's up.

wyclefsirocz

true, my car ran a 15.1 and its a damn 305 w/ the G92.
u give me any probly running 350tpi iroc or GTA w/o 2.7x gears and i will get it inot the mid 14's w/ a tune up.