Anyone have flow numbers on stock 8113 Corvette heads? such as CC runners, actual flow numbers, ect? valves? well i know i can get some cheap, and do a little bit of porting/polishing to them. i know they wont be as good as aftermarket heads but are they even better then stock cast iron heads? also is there a classifieds on this board?

 

*Roughly 200/ 170 cfm at .500' lift. (peak)
*Not even close to aftermarket unless heavily worked.
*1.94/1.55' valves (someone check me on that)
*58 cc combustion chambers
*163 cc intake runners
*Most will tell you they are an upgrade from aluminum, I disagree.
*Yes, there is a classifieds:

www.thirdgen.org/classifieds

Welcome to thirdgen.org, and good luck with your decision!

 

Thanks man! *Most will tell you they are an upgrade from aluminum, I disagree. ????? do you mean cast iron? do you think i can get enough power out of these heads with slight porting on my 400? (and prob. 202 160's)

 

Oops!!! I MEANT to say that the aluminum heads are considered an upgrade from the cast iron, and I disagree with THAT!!! LOL. Sorry.

I'm not saying that they are INCAPAPBLE of making decent power. I'm saying they need alot of work. There is a guy on here that posted a wonderful series (I wish it was a sticky of sort), of how he worked a set of L98 heads (iron I think...officially speaking, I think the L98 designation may only refer to the aluminum heads, but the iron heads are pretty much identical other than casting material and combustion chamber size) to flow better than the AFR 190/ 195's, which I find to be truly awesome.
Also, I have read articles in which a set of aluminum L98's (worked of course) suppported low-mid 12 second timeslips with the right combo on a 350 powered car, so the potenital is certainly there.

If I were you, I would CAREFULLY consider what you want to get out of these heads versus what you are going to spend. Also, it would probably help me (and everyone else contributing to this post) to know what your definition of "enough power" exactly is.

 

well i just want to barely brake into the 12's i want to get a cam but not a roller and i also need specs on the cam as in lift/lift dur/dur to know exactly what ill need for my TPI setup. i mean the porting i can do myself iv done a few sets of heads myself but as for making the heads well enough, someone on a different post was saying the heads in stock form are good for 350hp ,380 slightly ported, and 425 highly ported(1 person said, i forgot who lol) but all i want is to break into the 12's. with my 400 and a mild cam. and headers and all them goodies. i need to put up some wanted adds for a posi and crap like that. well when i get done this and race my brother i want him to be like lol but if i can get a set for about 350 i dont think it wouldnt be too bad if i put some time into them(iv got all winter) and 202's if need be. but are the l98 (alum) heads made with straight center bolt intakes or angled(pre-87)? i would think they are straight(post-86) but not 100% sure, anyways it will most likely come down to me buying a set of trickflo's or AFR's but i want to see what my options are here, im not going all out killer style.

 

Yeah, I read an article where these heads were used on a 3rd gen running 12's. Check out the magazine articles on this site, I think it was in there. I myself went for the AFR 190's, their on the way and I'm patiently waiting........

 

here ya go..I got this from here a great site about heads

 

The L98 head will support the power you want but it will take a lot of work to get it to. I just finished porting mine and they flow pretty good; (248cfm in @.480 and 181ex @.500) but this is after extensive port work. Stock they are pretty choked up. The port work itself took me about 45hours to do and around $350 in additional costs and I have a friend with a superflow600 flow bench so he didn't charge me for flowing the heads. I think you will be better off buying some pro action cast heads or going with some AFRs that won't need extensive port work to make lots of power.

 

hey all i can say is LINGENFELTER,from 355-406s he uses his modified vette/zz4 heads upgrades to 2.00-1.56 valves cnc port job and they work;91 z-28,383,lpe 219-540cam,1.5 cranes,superram,58mm,30lb inj.,perf.res.chip,2200 stall,slp 1-3/4s,3.23s,cut air boxes underdrive pulleys ran at HRP in "94 we ran 12.20s on bfg comp.T/As 245/50/16.....112mph!!!'87 vette with same combo ran 11.76@116......

 

Here is an excerpt from a racing engine builders page. something to think about when porting heads.

Fords and Chevys do not have an intake problem... they have an exhaust problem. If you've got a set of stock cast iron heads and had them fitted with 2.02" valves and think you're going to get more horsepower, you're just kidding yourself unless you did some more machine work and "un-shrouded", or relieved the valve area inside the combustion chamber PLUS added larger exhaust valves. You can actually lose flow by installing valves that are too big for the combustion chamber unless they are un-shrouded. It's pretty simple, what goes in, MUST come out! On hot street engines, you'd be better off leaving the 1.94" intake valves alone and opting for a set of 1.60" or 1.65" exhaust valves. Don't believe me? Look at 99.9% of all dual profile cams. Almost all of them have more lift and duration on the exhaust side than they do on the intake side. Gee, I wonder why?

Exhaust is the restriction on chevy heads.

 

I agree. The exhaust on some SBC crate engines suck. Most of the cams offered by GM performance is optioned for the ZZ4 engine. The ZZ4 engine has L98 aluminum heads, which have a poor intake/ exhaust ratio due partially to port design but largely contributing to this is the EGR passages in the center ports. This wonderful feature is good for about 15 cfm on the bench.

 

What EGR passages?

RBob.

 

vette heads don't have EGR

 

I have an article of an '89 Formula 350 that runs 11.7 N/A and 10.7 with the aid of a 125 shot. He had SLP prepped factory Corvette aluminum heads and a stock short block!!! So, the L98 aluminum heads have the potential if they are well prepped. How much does it cost for SLP or another well know company to work your heads with larger valves, etc... well, that's another story.

 

If its SLP, it will probably be 200-400 times more then what a normal person pays at a machine shop. If TPIS does it... 450 times at least.

 

screw that! if someone already has some used prepped heads then ill go that way but other than that ill probably buy some aftermarket ones.....

 

yeah who would send their heads out to get fully worked and get C&C ported by someone that is well known in the racing community and has prolly the best reputation in L-98 motors as well as other motors i know i spent my green backs in the right spot....i will do again..i have had tfs,edelpoops,none worked out the way my lil LPE modded heads worked,the only acception was my afr 210s but that was an entirely diff,motor,those sexy heads worked2.08 int. 1.60ex. that car went from 11.70s w/fully ported darts to 11.30s,yes i needed the larder heads but that was the biggest,baddest change to that motor,.04 on a head swap!!!!!!!!!!!!!!!!!!!!!!

 

He meant to say .4, lol

 

I have been looking into getting a set of these heads ported as well. Based on what I have seen, the work for getting a good CNC port job done on the aluminum L98 heads starts at around $800 and goes to around $1895 (Lingenfelter). Even with the cost of the AFR 195cc heads ($1299 for the Street version and $1974 for the Competition Package CNC ported version, both of which flow better (based on specs) than ported L98 heads and are emissions legal), I just can't see spending even $800 for CNC porting when I could probably sell the aluminum L98 heads for enough to offset the cost difference between the $800 port job and the $1299 cost of the AFR 1040's.

From what I see, I think my money would be better spent on the new heads.

 

I ported my own 113 heads and all i can say is WOW, what a difference! They dont need to be cnc ported to be good flowing heads. Do some research on porting 113' s and try it. This was my first porting job and it turned out fantastic. Not to hard to do at all, just time consuming. I put in 2" intake and 1.56" exhaust valves and had a 3 angle valve job done and did the porting myself. 500 bucks and the heads are back on and the car is amazing. just my thoughts. good luck

 

If noone has read this article I suggest to give a quick read. This is one of the best DIY porting articles i have seen.

http://www.chevyhiperformance.com/te...518/index.html

From the article you can see the intake ports are the least critical.

This is also in the database.

http://www.chevyhiperformance.com/te...98/index4.html

 

clipp do you have any times? or seat 0f the pants?? estimate? lol

 

Here is a link to a site that has some flow numbers too.


http://users.erols.com/srweiss/tablehdc.htm

Hope this helps.

Jake

 

no times yet as i was on the way too the track and it started raining! the worst part is that it was the last race of the season! the seat of the pants feel is tremendous! niight and day from stock heads to ported heads. two days after putting the heads back on i twisted the rear end pinion. It was a brand new richmond 3.73 pinon used less than a year. Ive got new gears now and soon as the snow leaves ill have those track times.

 

clippjr8: After the work on the combustion chamber, what is the volume? Also, did it lower your compression by any measurable amount?

Thanks

 

why can you only put 2.00 1.56's for vavles? they say the 58 cc chamber is too small but iv put 2.02 160 valves in 2 different set of 305 58cc heads and there both on the vehicles and both running. no cracks or anything,people said it couldnt be done but anyways, maybe different shapped CC's

 

I believe it has to to with the steel inserted vlave seats, along with shrouding problems resulting from the small 58cc chambers. Remember, a larger valve with more shrouding will reduce flow numbers.

 

So are the 2.00 and 1.56's enough for the power? also did you guys do extensive porting or just minor, or just cleaned it up?

 

Hey, i have a very nice set of zz-4 heads. ported and polished. should yield great gains over the stock heads. I was going to put them up on ebay. are you interested?

 

i did extensive port work on mine, 18 hours worth! the 2.00 and 1.56 valves are plenty for those heads. They flow as well as most after market heads but the cost is not far behind buying aftermarket heads also. I will not swith to anything else as i am very pleased with the performance of my ported vette heads. by the way, 2.02 valves will not fit on the stock seat of the 113's. I already looked into it and am glad i went the way i went on mine! good luck

 

although you were able to put 202/160 valves in a 58cc 305 head is not the issue they will fit,the problem is if you had a flow bench you will see that the head cannot flow the numbers to support valve sizes such as these,you will spend time UNSHROUDING the valve from the pocket,you did feel the car run harder due to the comp.ratio going higher but upper rpm is dead..

 

i had the shroud machined. but o'well i just need a decent set of heads, either new or used. for prob. 600 or less....