Here's what I was planning:

- Manley 2.02"/1.60" Street Flo valves
- Comp Cams 26981 "Beehive" springs with steel locks & retainers
- Screw in Studs w/ guide plates
- Port matched intake and exhaust ports
- Polished exhaust ports

What do you guys think?

I'm trying to bump up the power a bit without upsetting the computer.

Thanks for the input!

- Joel

 

Really? No feedback?

 

If you're trying to stay computer friendly then you probably don't need valves larger than 1.94"

I think you could get away with an LT1 cam in a MAF car without the computer going haywire. Maybe a modded LT1 intake as well to help your mid and upper range.

I'm not an expert on casting numbers - I look them up here when I need to. Do your 083's come from a 305? Seems like the budget ticket around here is to run LG4 305 heads or 305 TPI heads with the mods you want. Is that what you have?

 

083's are cast iron 350 heads, stock on my L98.

Cam wise I'm gonna use one of Crane's CompuCams:

104224 (270/276, 214/220 @.050", .452"/.465", 112) (CARB EO # D-225-22)

or...

104225 (264/270, 208/214 @.050", .438"/.452", 112) (CARB EO # D-225-22)

I'll be using 1.6's too so the lift numbers will be a tad bit higher but not over .500".

BTW, if you need to look up casting numbers, check out MorTec.com

 

For a factory head, 083's respond quite nicely to a little port work and a spring upgrade. I modded mine with porting on the intake, a little bowl and short side radius work, and polished the exhaust ports. I used Standard Abrasive's deluxe porting kit to do the work, and they turned out really nice. I also had screw-in studs installed and upgraded the springs. I didn't want to spend the money to have the spring seats cut for dual springs, so I got a set of Isky's 235D springs/retainers installed, which have almost identical specs as Comp's 986-16 dual springs, and they fit in the stock spring pockets. For the cam you're planning on using, Isky's 205D springs would be a perfect match. Unfortunately, I'm probably not going to running mine since I came across a deal on a set of AFR 190's that was too good to pass up. But they turned out to be a damn sweet set of heads after the work I put into them. 083's are a great set of heads for a mildly modified L98. A lot of guys work up the 081, 305 heads to bump up the compression ratio, but to make them work good on a 350 you have to spend the extra money on getting 1.94/1.50 valves installed. Speaking of valves, you really don't need to upgrade to 2.02/1.60 valves for your goals. A nice set of aftermarket, stainless 1.94/1.50 valves would be more than adequate. Of course the Vortec heads are one of the best flowing factory heads you can use, but then you have to fork out better than $400 for the special Scoggin-Dickey intake manifold to be able to use them with TPI. Not to mention the Vortecs usually need the guides machined down to run any lift above roughly .470. If you're ok with a CR of 9.0-9.5:1, I'd say working up the 083's would be the most cost-effective way to go, and with the port work they should flow good enough for the Crane cams you posted. Btw, you really wouldn't gain anything by using the 492's you mentioned in your other post compared to the 083's. Plus you'd have to router out the 4 center holes of your intake to be able to use them, or use a 85-86 intake.

 

Thank you for your reply Pat, that's the kind of info I was looking for! In that case I think I'll stick with the heads I've got and do some of the work you've suggested. What do you think about Manley or Ferrea undercut valves?

I do plan on going Vortec eventually, but that's a ways down the road. As far as the Vortec heads go, I'm torn between the RHS Vortecs and the GMPP Bowtie Small Port Vortecs, they seem VERY similar. Both are good to .530" lift, which would be perfect for what my intentions are. Eventually this thing will have a Procharger P1SC on it.

I worked out the EGR issue with going Vortec. I'll just buy the painted Hooker 2055's and have the EGR tube from SDPC welded into the primary, then send it off to Jet Hot to get coated... I'll even open up the ball flange a bit before I send em off, since that's really the only weak area of the 2055's.

Well, I guess I'll clean up the 492's and sell em to my friend then.

 

yeah, do some pocket/bowl work on the 083 heads, and clean up the castings inside the runners/exhaust ports. smooth it all out and they should pick up some good flow numbers, upwards of 20-25 cfm easily. although a 210-220 cfm peak flow isnt great by all means compared to aftermarket, its worth probly 15hp on a stock cammed motor and more with a bigger cam. stock LT1 heads flow around 215cfm and guys have made 350-360 at the WHEELs. its all in the tune and combo, i think you can pull it off.

if you want to run a powermax cam, go with that 224 cam.

keep your compression up and run premium gas with a good timing curve, you can see some impressive gains. stock L98 blocks tend to have the pistons about .025" in the hole. get a steel shim gasket about .015 inch thick to keep a good quench height, and should keep compression up around 9.5 to 1.

if you want mill the heads down to about 62 cc's and bump compression to 9.7 to 1 and it make more power.

i kinda wish i would have done some experimenting with them but i went with AFR 195's so we'll see what the combo will do.

 

Definitely go with the Manley valves, they're much better.

One small problem though: Once you spend that money to upgrade your stock heads, you're only a few dollars short of some aftermarket heads that will outflow anything you do to the stock heads, right out of the box. Just get some Trick Flow 23 degree heads from Summit and call it a day. Then you can run any cam you want up to about .600" lift. (or maybe its .550" lift?)

Also for headers you can get a set of Dyno Don's headers and he'll weld in the EGR tube for you. See the threads in the Exhaust forum.

 

The guy at my local shop quoted me about $450 for the following work:

- Fully cleaned/tested
- Surfaced
- 3 angle valve job
- Screw in studs w/ guideplates
- 1.94"/1.50" Manley Street Flo valves

This is assuming I'm providing the springs, locks and retainers, which I have a set of (981's) with less than 5000 miles on em.

I asked the same guy if I could go with any bigger valves without opening up the chambers and he said I could probably get away with 2.00"/1.60". That sound about right?

He said if I go with bigger valves it'd cost me about $50 more. So I'm still looking at about half the price of a set of Trick Flow 23's. Eventually I want to go with a set of RHS or Small Port Bowties Vortecs, then even further down the road a set of AFR 180cc Vortecs.

 

the bigger valves may give you an extra 5-10cfm of flow as is, but i dont think its worth the cost. spend some time opening up the bowl area, doing some mild pocket porting and smooth out the casting flaws in the ports, you'll gain more that way than a stock set of heads with larger valves. just use good 1.94 valves that are back cut and necked down and swirl polished

see this thread for 083 porting
https://www.thirdgen.org/forums/tpi/...d-project.html

he gained about 20 cfm from 2.02 valves over stock 1.94's but this is on heavily ported 083 heads. stock cast 083's may not see much more flow with 2.02 valves let alone 2.00's

 

Awesome read, thank you!

 

for the 450-500 is that guy going to hog out the bowls

if not it is not worth putting bigger valves in your heads

its like putting a bigger lid on a coffee can-just because the lid is bigger does not mean you can get any more coffee in the can

 

LMAO, That is the best saying I've ever heard! Yes, and blending required for bigger valves would have been included in the price but even if it wasn't that'd be fine cause I've done that job MANY times. I will be staying with the 1.94"/1.50" valves anyhow though so that's no longer a concern, y'all have convinced me. You know how it is, it's that "bigger is better" mentality, and even I need a gut check every now and then

So it looks like I will be installing Manley or Ferrea undercut 1.94"/1.50" valves and doing a fair bit of port work, though nothing to the extent of what was posted in that other thread.

Although... What about leaving the 1.94's and just installing 1.60" exhaust valves? A bigger lid may not let you get more in but it would sure let you get it out faster

 

i contemplated that myself before i went with AFR's. I was thinking it could really help the exhaust. After extensive porting the heads in that article above really liked the larger valves. they picked up 24 cfm on the intake and 16 on the exhaust. i think it would be worth it to install 1.6's on the exhaust just to keep the exhaust intake ratio up.

but if you go that far, you might as well go 2-2.02 on the intake.

 

Who's the shop? I might know them.

The Manley part numbers for the Street Flo 1.94/1.50 valves are 10722-8 and 10721-8. They are narrow-stem and polished but you need to do the back cut on the valve seat yourself. The 3/8" screw-in studs are 42106-16.

Installing new valves is not just a matter of removing the old and putting in the new. You need to install new valve seats and shape the port to match.

 

It's the Antioch Parts Depot (Carquest) on A street.

Do the back cut on the valve seat? I think that's what I was referring to when I said blend, or are we talking about two different things?

So 1.60's not worth it? I've actually found a set with 2.02"/1.60" already installed for $549 ($619 shipped). Should I just get these and do some mild port work?

Here are some pics of em...





I've asked for more pics and info, but what I know so far is that they've been given a 3-angle valve job, the ports have been opened up to fit 2.02/1.60's, and they have all new hardware including Z28 springs, SS valves, hardened seats and valve guides. They are being sold by the professional who did the work. I will post additional info as I get it.

 

what heads are those? Iron L98's? they look like they need some chamber clearancing to get rid of shrouding.

other than that it seems like a nice place to start. z28 springs suck tho. i'd upgrade those to someting else. if you want a strong single spring to fit into the pockets, manley 22410's i believe will get er done

 

Yeah, 083's.

I can probably get different springs installed for slightly more, I'll ask about the ones you suggested... You're taking into account the cam I plan on using right?

As for unshrouding the valves, I agree, but that's cake. Only things that sucks about removing more material from the chambers is the fact that I'll have to have the heads shaved again after I do in order to bring the CR back up, which presents another problem... Just how think are the decks on these things?

 

yeah if you go with one of those compucams or something similar with lift under 500 and duration under 224 intake at .050" lift, then yeah, those single manleys will be plenty of spring. if you go any more than that i'd go with beehives

not sure how thick the decks are, but its generally .006" per cc. I'm sure the heads can handle .020" easily. that about 3 cc's so it should bring you back to 64ccs if you open up the chamber 3cc's or so. I'm not sure how much it will actually change if you do some more unshrouding. but if you do lose alittle compression it wont be a huge difference with those cams

 

Honestly, those heads are old school technology.
After you spend all that money on them you will have regrets that you didn't go with something better.

Do it now and save yourself the grief.

 

You haven't read the entire post have you?

 

Bought the heads, got em for $576 shipped with insurance! I'll take better pics when they arrive.

Also, as an added bonus, my girlfriend got me a $200 Summit gift card, so here comes the Crane 104224!

Next on the list is the Edelbrock base, SLP runners, and quite a bit of time spent with my die grinder.

I'm hope'n that with this being a MAF engine and having a 2000 stall that I'll see nothing but gains.

 

When I redid my 083's for the camaro I went with Comp 986 springs, new locks and retainers. Stock intake valves and Manley street 1.5 ex valves (Hey they were on summits scratch and dent rack) 3 angle valve job and I pinned the studs. Paid about 350 all together. So far so good. They really love the blower