got a call from the machine shop today and i was told that my block was oval in #4 and #7. they told me my best bet was to bore it .020 over. i have been wanting to do that but before i do i have a few questions. first my buddy of mine said that if the block is oval the crank needs to be shaved???? also i just picked up a set of 193 casting number heads and they have been worked on they have 2.02 intake and 1.6 exhaust valves on them with stock springs and stuff. i wanted to know if i bore out my block do i need to get a new ( or shaved ) crank. and will i need a new cam. the motor originally was an 88 350 tpi i have the stock hydro cam and lifters ( out of an 88 GTA ). if i do need a new cam what cam do i go with. ( trying to save money and gas this is going to be my daily.....yes i know i'm crazy). please advise. i'm fairly new at building a motor and i don't know THAT much so explanations would help out also.

 

if ur reusing the old crank it needs to be inspected along with the main bearing journals if clearances aren't to spec turn the crank and line hone the block andd i would make sure they rebalance the assembly + - 1 gram

 

Oval in the cylinders has nothing whatsoever to do with the crank.

When the block is bored, it will need new pistons; and of course, new rings. Might as well get the crank turned and replace the bearings while it's apart; although, the "oval" situation, by itself, doesn't require it. If the crank has only just a few miles on it since it was last turned, it might not need it. Your machinist can tell you for sure.

193 heads are garbage. There are few castings that would be any worse. They have the "swirl port" design, with the big ramp-shaped lump in the intake port that's supposed to make the incoming charge "swirl" at low RPMs as it enters the cylinder. It is intended to improve low-RPM torque, at the expense of any kind of useful performance. Doesn't matter what size intake valves somebody stuck in them, they still suck. Get rid of them. Get a set of 081, 416, or similar NON-SWIRL-PORT 305 heads, and have 1.94 intakes installed in them, and give them a gentle bowl blend job. See this website for how to do it. You can order the "kit" from Summit or wherever, or likely get it from your local speed shop.

For a decent but not too $$$ cam, I'd suggest a Comp XR270HR. Since your block is a roller and you already have the roller stuff, there's no sense in downgrading to a flat tappet, and taking the risk of having a lobe wipe out at startup. That will QUICKLY evaporate any "savings" you might think you're getting by using the lesser kind of cam.

 

Or use the origonal 350TPI heads that came on that TPI motor. Casting number ends in 083. The 193 swirl port heads are a step down.

 

i kinda understand what you are saying but why would i go with 305 heads when the stock ones were 350 heads(193). the ones i had were shot and the reason i got them was because it had the same casting number so i figured it would bolt up and i would have no problems. They were also not that expensive i got them for just under 300 and they have been cleaned, cracked tested, magnafluxed, a 3 angle valve job, and resurfaced .010 with larger valves.

 

Because the 193 castings are GARBAGE, and those PARTICULAR 305 heads are better. Not ALL 305 heads, mind you; there are 305 castings that are just as bad as, if not worse than, the 193s, such as 187 for instance. That's why I gave you the casting #s to look for.

I might add, the stock castings from a TPI 350 were 083 casting, as F-Bird says; which is CONSIDERABLY different from those crap "swirlies". That one would also be an acceptable one, if you came across it. They're not bear as common though.

193 castings are "stock", but not for YOUR car. They are truck & Caprice TBI heads. They will prevent your car from even reaching the minimal performance it was capable of when it WAS stock, before it suffered the downgrade to the TBI heads.

There's a reason you got the inferior ones for so cheap. It is because they are GARBAGE, that no one who is looking for performance and knows what they're doing, will want. Only people with TBI trucks and Caprices who are willing to accept the stock heads for THOSE applications without upgrading them, or people who don't know how bad they are, will accept them. But you're here, which automatically makes you smarter and gives you access to better information than THOSE people; so take advantage of the knowledge available to you.

The normal and customary repair work you describe being done to them does not make them more valuable. Neither does stabbing the larger valves in them. I suggest you get rid of them; maybe find somebody else who will pay you what you paid for them so you don't lose any money and you can start over with something better. After all, if that was a good deal, it shouldn't be too hard to find someone who considers them valuable enough so that they're equally willing to pay what you've got in them, right?

081 or 083 heads will bolt up exactly the same as those garbage ones; same intake bolt angles, centerbolt valve covers, etc.

 

Neither TBI nor TPI heads heads flow well in stock form. Both can be ported to flow very well. Both of these statements are proven here:

https://www.thirdgen.org/forums/tbi/...-headflow.html

With that said, none of the above work done on the heads will make much of a flow difference. The bowl needs to be ported, and the valve guide bosses and swirl ramps need to be radiused. If you don't have those items performed, then your heads won't flow much better than stock heads.... and the oversized valves won't help because they weren't the biggest restriction to airflow even when they were stock.

You should also make sure the valve guides are still ok.

If you want to save money then you have to decide on the fiscal choice between keeping what you already own (which will help fuel economy but give up some performance) or sinking another $500+ in used heads + intake manifold and get more performance (assuming you tune the combination). This is less of a performance tradeoff than it is a money tradeoff.... because both approaches (ported factory heads, or Vortecs) can be made to work.

 

what i was trying to ask is IF i use the 193 heads with the bigger valves do i NEED to change the cam or can i use my stock one. my buddy told me that i HAVE to change the cam because it wont run correctly. i was just going to install the motor as close to stock as i can for now and work on it little by little. (pulling the motor out to change things isn't that big of a deal for me). i am going to use the stock intake because i have done a little work to it and i don't want to sell it just yet. i may end up re selling heads and getting a 083 casting.
i just don't want to start this motor up and nothing works or i get worse gas millage then i do now ( currently a v6 with over 105,000 and im getting 9-10 miles to the gallon ) yeah something is wrong there.........

 

No you won't "need" to change the cam, if you use the 193s.

Those castings will protect the cam from ever making any difference at all. Just like the excessive valves.... if they're not the restriction, then it doesn't matter how large you make them, it won't change the overall flow. Same with the cam. About all you can do with the cam is to shift the RPM band that the cam favors so far out of the range that the heads work in, that the motor won't make power at ANY RPM. Too large of a cam will make the bottom end soggy, and meanwhile the heads will guarantee the top end to be non-existent no matter what.

 

Don't over dramatize ---- Lo-tec went 13.6 with stock 193 heads and a 210 deg cam + exhaust.

ssj2link: if that level of performance is enough (mid 13s), then the 193 heads are fine.

 

trying to sell the heads. and im getting a set of 083 casting heads. they have been checked and come with comp springs and guide plates. now i have another question. i gotta bore my motor 30 over. now i need to know what pistons to get?

 

What kind of budget are you working with?

 

not a big one i was looking at the .030 Flat Top Speed Pro Hyperutectic Pistons they are in my price range they are like 70 dollars. just want to know if there is anything around that price plus or minus a few bucks. i also dont want to have to replace them so im looking for quality. the block is gonna cost me 260 to bore and hone.

 

Those will give you .020" more deck clearance than stock; which will result in quite a bit lower compression. Other than that, they'd be OK.

If you can stand about $200, look at these. http://store.summitracing.com/partde...2DKB198030%2D8 They'll preserve your stock compression, without having to use risky thin head gaskets.

 

im new at this as well. if i get the 70 ones will they work with the stock rods and pins. i just found these as well: http://cgi.ebay.com/ebaymotors/CHEVY...QQcmdZViewItem
will these be okay. im on a college budget and i dont have a lot of money. and as for the compression thing i dont understand compression ratios at all. i kinda need an explanation or a course lol. is it the higher or lower the compression that is wanted. im looking to get good MPG out of it as this is my daily driver.
thanks for all the responses.