In a high performance engine for sure use nice forged pistons but in a mild build with a mild cam and no power adders. I still would not mind using those pistons and make the power under 5500.
I took that .040 off because I wanted to bump some CR without touching bottom end. Now I think that wasn't so smart move. I'd like to put bigger TA stainless valves but is that make any sense for those heads? I mean is there any surface left for future? Or should I find new pair from you US guys? I changed TA satage 1 valve springs last winter because old springs caused valve float at 4500rpm (1 exhaust valve hit piston and bent pushord). Combustion chambers are still round. https://www.dropbox.com/s/ew18xv6rbdswi65/2015-10-31 16.27.13.jpg?dl=0 I think Im fine with cast pistons (because my budget is limited like always ). I don't like revving over 5000rpm anyway.
The bigger valves would still need new hardened seats installed. They are only .050" larger on the exhaust. There is not enough material remaining in the head to just cut new seats. You old springs being weak hammered the valve seats down from bouncing and floating. Weak springs cause more damage than too strong of a spring.
When I changed springs I hand lapped valves and all seats were nice and narrow, hammering happened with stage 1 springs. I also changed exhaust valves then, maybe those cheap rockauto valves cased that? In those heads they are already 1.550" like in TA stainless set. Exhaust valve size goes from 1.500" to 1.550" in -75 or -76 heads. I really have to think what I should do with these heads...
Asked prices for valve job: seats 150€ per head, guides 10€ each, hardened seat rings 30€ each = 720€ (€ and $ almost same now). With valves ~1000€ What kind of prices you have there? edit. btw check my pictures from finnish Buick meeting at last summer: https://www.dropbox.com/sh/4f86dn6thtiu133/AACZHRRPAyV7EM4YGNy-IfFba?dl=0
Yes it costs about $1000 or more to have heads rebuilt with oversized valves. All the more reason to spring for the alum heads... I got an update about the heads a few days ago but was sworn to secrecy about the details... Lets just say the 350 alum heads will be a game changer.
Are u guys using lead additive in your Buicks? I did not, and now Im thinking Im stupid and that destroyed my valve seats?
I doubt that running without lead did any problems . leads has been gone from fuel for 20+ years. Driven plenty of those cars as daily drivers. Never seen much problems.
I have this Comp's cam now: http://compcams.carshopinc.com/product_info.php/products_id/71040/92-202-4 If I change to Crower level 3 will I get any improvement, numbers look pretty close to me? http://www.crower.com/buick-350-compu-pro-hydraulic-cam-276-hdp.html Intake lift and duration is little less at .050 in Crower, exhaust side is bit bigger. Lobe separation 112 vs. 110.
I do not think I would bother switching to that cam... Did you sort out your pistons and rough estimate of the compression ratio? That will tell you what you can do for a cam... If you have over 10:1 compression you will want a big cam to bleed off some compression. If you have under 10:1 I would keep the cam you have.
I would agree with Sean on figuring your actual compression first. 9.2-9.8 I would go to the Crower. Probably see increase low and mid torque with a dual pattern cam over the comp cam . if you have 9.8 or more think about the level 4 or TA 310 ,413 cams. Would give up lower end for more upper . higher stall convertor and deep 3 series rear end.
I have around 8.8:1 now, if I change v6 pistons with smaller dish I'll get 9.7:1. I have 2000 stall converter and 3.08 rear and Im fine with those.
You could try the level 3 cam with 4 degrees of advance. With the convertor and gear you have should pull well. The level 2 cam would work well also and is really matched for that gearing. The 212 would work . compression is really what holding you back. Shaving heads later down the road is an option then. Another .030 can possibly put you 9.3 ish. Which should net good power with any of those cams without needing to go into bottom end. Which v6 pistons are you looking at.
OK. In a Buick 350, close to stock configuration, on planet Earth. A cam with 112 LS will idle better, provide more low end power and better fuel economy than a cam with a 110 LS. Better? And yes I idle everywhere I go!
I like to idle too! And I like low end power so maybe I'll get new pistons and Crower 3. And if I someday stop being poor pistons will be autotecs.
Lobe separation is a by product of the 4 major valve events. It has zero bearing on a cams power band. It is merely a by product of the aforementioned events Not directed at you Steve. . Just trying to educate folks is all If I were to ( and maybe I are ) build a street car, rest assured I wont run anything near what most off the shelf cams are built like.:Brow: Oh and before someone says it, headers or not wont change my mind :laugh:
