Please help me to choose properly the heads size


1991 L98 automatic 2.59 rear end

I already bought some parts

Mods

Trans and rear end

1.-2200 stall converter (bought it, not installed)
2.- 3.07 rear end (bought it, not installed)
3.- transgo (bought it, not installed) and oil cooler
4.- beam plates (bought it, not installed)
5.- speedo gears, red,green 92 sensor for 3.07 (bought it, not installed)
6- nitto treadwear 100 installed

engine

1.- Long tube headers installed
2.- no cats, doublé 2 1/4 exhaust to borla mufflers installed
3.- 3 wire heated 02sensor installed
4.- 1.6 rr self align installed
5.- stock 48mm throttlebody
6.- edelbrock ported base manifold AND slp siamese ported runners(bought it, not installed)

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7.- lt4 springs (bought it, not installed), afr springs I supose are better option for 268 xfi cam
8.- 30 lb injectors (bought it, not installed), I red that 24 is enough but pcmforless suggested 30lb
9.- walbro 255 fuel pump (bought it, not installed)
10.- k&n,cutted airlid,adjustable fuel pressure regulator installed
11.- msd 6al installed
12.- moates apu1 for fine tuning installed
13.-pcmforless chip not boughted until buy cam (baseline)
14.- egr, frisbie,airpump deleted

brakes

15.- c5 front discs, calipers, zr1 booster, hawk racing pads,stainless hoses


I wanted 180cc afr heads and 268xfi cam

the Price between 180cc and 195cc is the same, I know that I will need to reduce combustión chambers.

what is your advice about the size of heads ?

I dont use this car as daily driver and I dont use it as drag car (maybe 3 times a year), I use it for fun and ocasionally trips

difference in torque and hp ?
bigger body throttle is needed ? 52mm I guess, not 58mm

edelbrock base is heavily ported to work with 195cc heads probably reach 5500 rpm with thsi intake

I dont have the camshaft then I can buy another model if is better for this setup

i have the car since new, only have 50,000 miles, the engine is running strong, I dont plan to stroke it to 383 then if leave 350cid the 180cc is better option ?, I red that 195cc Works great on 350 and you have opportunity to grow later but this is not my plan

 

My car runs 12.80@108 with a zz4 and 180s. If you are not after max power, 180s are fine.

 

Do the 180's and 195's have different port sizes? Like 180's being a 1205 and 195's a 1206? What size port is the intake? I think 1205's would be good for what you are doing....my stock Edelbrock manifold is a 1204. At least port it to 1205.

 

1205 is (I bought Felpro 1205)
Felpro 1205 port size 2.09 x 1.28
Felpro 1206 port size 2.21 x 1.31 afr 195 are these size ? huge !

I sent my base to port job, this was the result that sent me :

this is stage 4. The manifold will flow around 300 cfm.

Before porting- the outlets (head side of the manifold are 1.25" x 1.98". The inlets (runner side) are about 1.55".

After porting- the outlets (head side) of the manifold are 1.28" x 2.09" (Use Fel Pro 1205 gasket). The inlets (runner side) are 1.65".
Bead blasting is process that removes dirt, grease or other materials. It also leaves a smoother surface inside the ports for better airflow

 

let me know if I´m wrong

AFR site says :

intake port gasket size

180cc =1256 = Port Size: 1.23 x 1.99''
195cc Street pkg = 1205 = Port Size: 1.28 x 2.09''
195cc comp pkg = 1206= Port Size: 1.34 x 2.21''

then my intake can be used properly with 195cc Street heads ?

 

No it wont neither will the runners.Who told you that?



195 might make 5 more hp 180 should net around +10 lbs tq with what you have. if it were me Id go the 180

 

hahaha, yes, I supose that 300cfm is difficult even without runners, who told me, the guy who sold me the port job

195cc 5 more hp than 180cc
180cc 10lbs more than 195cc
with this setup, 180cc will be cleaver, I supose 195 need a more efficient intake

what is your opinión about cam 3.07 rear end and 220 stall converter ?

268xfi supose is good for midrange operation I like the idea and compcams say is good to 5800 rpm, I dont believe that my intake can reach 5800 rpm maybe 5400-5500 rpm

 

Powerpigz was wrong with his gasket correlation. I have the 195's and they match up (quite nicely) to a 1205 gasket. But he was right about them having different base port sizes. The 180's are probably the better choice -- if you're sure you'll stick with a longtube intake. They generate a bit more air speed at lower rpm and will run out about where the longtube intake does. You'll get the best performance with the 180's in the lower/mid rpm range.

OTOH, the 195's will perform just fine. I have the same intake -- though ported (by myself) MUCH, MUCH better than whoever did your so-called 300cfm job.

Count on 210cfm at the most. 180's flow WELL above that.

FWIW, I think you're better off staying a hair below the XFI lobes. I think it's the Extreme Energy series that preceeded the XFI's. Kinda depends on how often you want to change (refresh) springs. 2yrs max for the XFI cams is what I've heard.

 

what means otoh ?

180cc are great heads and if my intake dont obtain gain with 195cc I prefer the velocity and torque of 180cc (need torque for my 3.07)

I always red good reviews about 268 cam and I like the high lift, I supose take advantage on heads like afr ?

I already have 1.6rr installed

cam options

268xfi
218 -224 570/565 1.6rr 113deg 5800rpm, I like this cam at specs,

08-304-8 266hr14 5400 rpm with 1.5rr
210/220 .500/.510 1.5rr .533/.544 1.6rr 112deg

08-422-8 xr 270hr 5400rpm with 1.5rr , same duration as 268xfi but 110deg idle will be roof and fuel economy is higher,but more power at midrange, less vacuum for brakes
218/224 .495/.502 1.5rr .525/536 1.6rr 110deg

another cam advice ?

 

check with AFR; I believe their heads are set up for use with guide plates and hardened pushrods which might conflict with self aligning rocker arms; but then again maybe they can use either; never hurts to check.

 

I was not stating anything, I was asking what the port sizes were on AFR heads, as I didn't know. Sounds like he could use either size head with his ported intake, which he could anyways, as long as the manifold covered the head ports. Not sure what the results of having a medium port intake/195cc large port head vs. medium port intake/ matched port head with smaller 180cc runners. I would think matching the heads with the intake would be the best all around decision.

 

Good question/point.

Eduardo should purchase both intake gasket sets and place them on his ported intake. If the 180 gasket is much smaller than the porting job, he’s better off with the 195 heads (in my opinion). I’m running that intake with the 195 heads and there is no problem with idle/off-idle torque. The 195 head is superior is a couple of ways. Because it has a minimum cross-sectional-area similar to 180 heads of the past, it maintains port velocity closer to 180 heads – but it flows more air than any 180 head. By a good margin – especially at lower lifts.

There are a couple of reasons I picked the 195 head. I maintained the ability to upgrade intakes if I wasn’t happy – and get better flow. They still have great port velocity and work REALLY well in lower rpms too. You can use a lower lift cam, maintain better top-end longevity, and still match (or better) 180-flow numbers because of the lower lift flow.

The best reason to pick the 180 head is when off-idle and lower rpms are really where you’d like to excel. Once you get to 1500 rpms, the 195 head is going to kick the crap out of the 180’s. 180’s probably will provide the better mpg numbers.


Eduardo,
OTOH = On the other hand.

AFR heads do come with hardened guide plates. You’d have to remove then to install self-aligning rockers. Stock L98 guide plates aren’t hardened and were only installed as an assembly aide.

That 210/218 can with .544” lift would be a very good choice as a torque cam. Likely more reliable than an XFI cam with an immeasurable loss of power.

Install your cam with 4-degree’s advance (if no advance built-in) for best torque performance.

 

Interesting thread Eduardo, i was on a very similar spot three years ago.
I chose the 195's, with the performance bug bitting maybe in the future
you'll want a different intake and the 195's will let you grow. If you are 100%
staying with the long runner setup, 180's seems to be better as far as i know.
But if you want more power all around and you are looking for a new intake in the future
Get the 195's they will perform very well with your current setup.

Check this old threads of mine, you might learn one thing or two:

http://forums.corvetteforum.com/c4-t...ning-this.html

http://forums.corvetteforum.com/c4-t...ombo-make.html

http://forums.corvetteforum.com/c4-t...-go-1-6-a.html

 

Looks like a good job, matching 1205 gaskets

 

In that case, don't think twice. Get the 195's so your ports match up. The port mis-match will negate any benefit of having the 180s over the 195's. (somehow I missed that your intake was already ported out to a 1205 gasket!!!)

You won't regret it!

And...like I said you really won't "need" as much cam with those heads.

I double my vote for the 210/218 cam you mentioned. Lingenfelter also offers one of similar specs. I also like Bullet for fast delivery and good service. Custom make any cam there easy... Not much more than a Comp cam.

Even a Hotcam with 1.6 rockers would be good. Milder ultra-longevity lobes with a bit more duration would offset duration versus lift to get similar flow. Plus, I love the lopey sound of a hotcam. Hotcams and good springs would last forever.

A single-pattern cam is a GREAT choice for long-runner intakes with STELLAR exhaust flow. With 195’s the exhaust flow is SO good, you don’t really benefit from having addition (split) exhaust duration. It actually serves you better to have a single pattern can (int duration=exh duration). Leaving the exhaust valve closed a bit longer raises compression – and improves torque. The sound (lope) is a little different though.

Lingenfelter's "superram" cam LPE219 would work really well installed 4-degree's advanced. And, it's a single-pattern cam. That would give a bit more compression and torque you want. Same level of lift as the XFI cams. Almost identical LSA too.

 

Go with the 195's for future growth and I would suggest looking into the competition port version of the 195's also.

 

I got the normal street 195's but ...i still have the doubt about the comp version of them,
i decided to stay with normal port because mine is a 355 not a 383 if i recall about my choice over the comp. They were $ 500 difference as well

 

I'd have serious doubts about the benefit of spending $500 more for comp ports for a long-tube TPI motor!

 

not worth it imo
That intake is choking the heads as is. Even with a very aggressive port job to the intake think his street 195s are still plenty.

Dont think 1.7s are worth it. Save up stroke it if you want more

 

calderone:

great links- good Reading

My case was diferent, I always wanted a superram but I never found a good one at correct Price. Then I wanted and edelbrock proflo xt and later a modified stealth ram, but I dont have time to adapt this setups, then this was the easier, I bought at ebay at 300 usd both edelbrock base and siamesed runner and I sent to port job.

195 competition I believe is too much and the diference at intake ports are huge ,195 competition are afr 210 modified if a red correctly.

then we need to port even more the base and the runners inside diameter are not big enough, maybe asm or edelbrock but slp are smaller.

AFR site says :

intake port gasket size

180cc =1256 = Port Size: 1.23 x 1.99''
195cc Street pkg = 1205 = Port Size: 1.28 x 2.09''
195cc comp pkg = 1206= Port Size: 1.34 x 2.21''

what about your hedmann header, I have the same headers, is true that are smaller for 195 exhaust ports ?