Need input on 383/396 and cam selection
What are the pros/cons of 383 vs 396? I recall reading something about the ringlands being weak on the 396 pistons due to the high pin location...is this right? I know that the more inches, the better, but I want this engine to hold up for at least a couple years.
I also haven't decided which heads I am going to use. It's a toss up between some ported out stock heads (stock valve size) and a set of out-of-the-box Trick Flows. Since I haven't decided on which heads I'm going to use yet, I haven't decided which pistons I should get with the rotating assemly; The -16cc dished pistons will give me ~9.8:1 cr with the Trick Flow's 64cc chambers, but what would the stock head's 54cc chamber give me for cr with the same piston? I'm sure the -5cc flat tops will be too much cr to run al the nitrous I want to, right? Which piston/head combination will give me the the best cr for what I want to do with the car? How about the best head gasket? I was thinking of using the Impala gasket to get the quench tight.
The cam I want to use is the XFI 468 (grind number 292XFI HR 13). Do box-stock Trick Flows or ported stock heads flow good enough to support the demands the stroker/cam are going to need? I know you make power in the heads, but I'm on a limited budget, and most of the money is going toward the shortblock.
Thanks for any help and advice you can provide.
Last edited by SprayedLT1; Mar 3, 2007 at 04:12 PM.
My reasoning for wanting the stroker now is so that I have a good platform to build on in the future. My engine is thrashed right now (something in the bottom end, probably a spun bearing) so a rebuild is necessary. If I do the stroker now, I will be able to drive the car, and it should run pretty well, even with stock ported heads I imagine. I can always do better heads next year, and when I do, I will have a good strong shortblock with more cubes.
I say stroke it and build you a bullet proof shortblock for the future.
So if I had around $1k to spend on heads, would I be better off with re-worked stock castings, or out-of-the-box Trick Flows?
Your stroker is not going to perform well for now, simple as that. I understand why you are looking to do the shortblock now and think it a reasonable decision, you just have to understand your heads are going to be the choke and that you will very likely endup redoing them when money permits.
Despite what the bench racers will tell you the stock castings worked by a good shop will feed your stroker, but depending on who does what budget porting now they may not really be any good to send in for more serious porting later. Kind of a tossup here either choice will require more work down the road.
On the cam IMO too big and I have not seen the XFI grinds particularly performing though everyone loves to recommend them.
An Eagle "balanced" rotating assembly should be rebalanced, by the time you are done with all that cost I would look at a Compstar Speedpack end cost will be about the same but the Compstar kit will be balanced much better right out of the box. Think the piston selection is a little limited as I don't think Mahle has a nice d-dish offering so this might make the head decision Trickflow.
At least look into it at Summit looks like the Eagle kit is like $1970, and you should rebalance which I think will be $160+, the Compstar stuff I think retails about $2100 and is Mahle pistons if you look into Compstar it is basically a Callies "budget" line, select offshore forgings with final machining done here. If I had the budget to do a fully forged rotating assembly this is the one I would use.
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As far as your top end and cam selection, it depends on your head flow, compression, and cubic inch. My cam is a Comp solid roller with a .650 ish lift, 248-254 duration @.050, and ground on a 110 lobe seperation. I don't street race and I am not secretive about my combo, so I have no problem sharing my specs with others on the forum. This cam may not be for you. My AFR heads after serious porting flowed 313 cfm and my compression is closer to 12.0 than 11.0. The heads have a 3/4 inch deck height and use Cometic head gaskets.
If I were you I would go with the 383 setup. Forge the bottom end and select a cam based on your head flow and compression. You should have no problem reliably spraying a 175 shot and going with a larger broken up shot on occasion.
Good luck with your build.
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For now we already know your heads are going to be the choke in the system because of your budget so don't let anyone tell you you have to match the cam to the heads now, buy the cam that should work well with the later head upgrades if possible. We already have a pretty good idea of what the various LT1 head options flow at what lift so the "match the cam to the heads measured flow" is grossly overrated, anyone helping you pick the cam should know enough to make reasonable assumptions on what the eventual heads will flow and at what lift.
Or you could just blindly throw money at whatever sounds cool
. Heads- Trick flow are good peices, I would have them milled good, Lloyd elliot does good work and when I was deciding on reusing my cnc ported lt1 castings there was an issue with the -16cc pistons and the combustion chamber of the heads, you should be able to run with a 5.7" rod, flat top pistions and a little milling to give you a comp in the 11 to 1 range which is good for juice anyway.
In would contact Lloyd about the cam, since he works with Bret on the grinds, he can find you a good heads and cam combo that will work well with the 383 block.
Heads- Trick flow are good peices, I would have them milled good, Lloyd elliot does good work and when I was deciding on reusing my cnc ported lt1 castings there was an issue with the -16cc pistons and the combustion chamber of the heads, you should be able to run with a 5.7" rod, flat top pistions and a little milling to give you a comp in the 11 to 1 range which is good for juice anyway.
In would contact Lloyd about the cam, since he works with Bret on the grinds, he can find you a good heads and cam combo that will work well with the 383 block.
Thanks for the info guys. I think I'm going to just go to a few local machine shops and talk to them about what I should do. If I can put together a solid shortblock with the stock crank and just use good pistons and rods, and save a lot of money compared to the stroker, that's what I'll do. But, if the stroker is only going to cost a couple hundred more, I may as well spend the extra $$. Whatever I end up doing for heads, they will be re-done next year anyway, which is why I'm leaning toward TF's for now. I just don't have the funds to do an awesome head now, and if I did, they would just be sitting on top of an engine bolted to an engine stand. At least with shitty heads, the car will be running...maybe not as good as it could, but I'll be able to drive it.
Thanks for the info guys. I think I'm going to just go to a few local machine shops and talk to them about what I should do. If I can put together a solid shortblock with the stock crank and just use good pistons and rods, and save a lot of money compared to the stroker, that's what I'll do. But, if the stroker is only going to cost a couple hundred more, I may as well spend the extra $$. Whatever I end up doing for heads, they will be re-done next year anyway, which is why I'm leaning toward TF's for now. I just don't have the funds to do an awesome head now, and if I did, they would just be sitting on top of an engine bolted to an engine stand. At least with shitty heads, the car will be running...maybe not as good as it could, but I'll be able to drive it.
I saw the sig pic
If money is tight, thats the way it goes but i'll say this, I dont know your time frame but my 383 is coming up for sale, I plan on putting new bearings (cam, main and rod), rings and possibly pistons which will be SRP -16cc dished units, the same I had before, im still figuring out a price the piston alone are like $550
But I dont sell junk, its got 4 bolt splayed main caps, eagle h beam and callies dragon slayer crank.let me know what your planning on spending on the short block.
My short block is close to this.... http://www.golenengineservice.com/sp...383compsb.html
which goes for $3600 not including shipping.
Something to think about, just putting feelers out there If I get someone hot, ill put it back together to ship.
I just got my headers for the transam and I am putting the 12 bolt in



