I will be building a 383 in the future (next year) and I'm going all motor, so what is the highest CR I can have with still running pump gas and still have the car street-friendly? Also what shoud I do to accomplish this, mill heads, pistons? Hopeing to get 17+ with fuel injection and tremec on freeway. With a comp cam 230-236Dur.05 and .490matched lift with 112lsa. and vortec heads,with work done to em.

I run 10:50 with out any problems with initial timing set at 08 on the balancer on a .60 over 396 L78 with stock dist. I've run 12 but it pings when it's hot out. I also have an L78 with 11:1 and you have to turn the timming down so much it's not worth it, also a stock motor.

Thanks for the info 66 ss, Anyone else, anyone running a non stock car with pump gas with 11 cr, without pinging?

Also, can I do a 400 build on my scoggen dickys 350 crate motor with a 4.125"bore and 3.75" stroke with (5.565" rods)? or will I be boring my cylinder walls to thin?
Sorry I'm just thirsty for information on this stuff.

you can not bore the 350 block that far. Most say .060 over for an over bore of 4.060. You can however go with a 3.80 or 3.85 stroke crank smile.gif

thanks, I guess I will put up with a 398 instead of a 400. What stroker kit do I have to get to accomplish this though.

10.4.1 on my 540 38 degrees total timing dart alum heads never pings

383 with forged flat tops and 10.9 to 1 in Arizona with iron heads on 91 octane. Timing is @ 6* in the summer, but still kicks the ricers around. As long as you zero deck the motor, you can get much more comp. ration out of it. My 355 is running 10.5 to 1 with iron heads and a XE 264 cam with full timming and never pings. With aluminum heads, I wouldn't be afraid to go to 11.5 to 1. Zero decking is the way to go. Most engines will ping at idle so get a cam with at least 235* dur. or more and you should be fine.

I run 10.7:1 in my 460 Chevelle with iron closed chamber heads on 93 octane. 37* all in by 2100rpm, no vacuum advance. 555hp No pinging at all.

IMHO, it's foolish to push it for a street car. Stick to 10-10.25:1 tops. You'll be on the edge at 10.4, imho. Unless the Vortecs are radically different than bbc heads.

Frickin' toluene screws up the seats in the Holleys.

Chad runs a nice solid cam in his vortec headed motor, bet he's not over 10.5:1. I think it's 10:1.

k, I think I'm going to go with the 10.1-1 compression, I still don't know what stroker kit or brand to get for the motor though, any suggestions guys? I will be going with a holley c950 fuel injection and this cam 230-236Dur@.05 and .490 matched lift with 112 LSA. Also I will be going all motor, "bottles are for babys" so I want the most power possible.

If you really want to go out to 398 cubes, you're going to need a 3.85" stroke crank.

To accomplish this, you'll need rods that are designed to be used with a "small" journal crank. That way you cam have your 3.75" stroker crank, which is usually designed to be used with "medium" journal rods.

So, in stock form, your stroker crank has rod journals that measure 2.10", and you need to have the rod journals reground to 2.00"(this is why you have to use the small journal rods). This .10" difference turns it into a 3.85" stroke crank.

Now, the tricky part is finding the right pistons.

With 5.7" rods, you want pistons that have no more than 1.400" Compression Height.

With 6.0" rods, you want pistons with no more than 1.100" Compression Height.

If you use 400 rods, you want pistons with no more than 1.535" Compression Height.

Maybe Wolfplace(Mike Lewis) will chime in and help you out.

Okay so will this kit work for that application.
http://store.summitracing.com/default.asp?target=esearch.asp&N=100&Ntk=PartSearch&Ntt=ESP-B13005E060&x=0&y=0
The only thing I see wrong with it is that it doesn't say the specific piston compression height, and the cylinder compression ratio.

You could hunt down a 400 shortblock to start with and sell the 350 to recoop your money, Use the factory 3.75 400 crank. Buy some good rods and pistons. You'll make more power with less investment. And the tremec would like the lower rpm torque in high gear. Just an idea, they are out there if you ask around.

Ya the thought had passed my mind and I would have done that before but my dad wouldn't let me when I first got the car in my senior year in high school, and besides the motor I have has like 6,000 miles on it and I know what has happened to it all 6,000 of em. Ya so Slowpoke70 will this kit work? http://store.summitracing.com/default.asp?target=esearch.asp&N=100&Ntk=PartSearch&Ntt=ESP-B13005E060&x=0&y=0

I have a 383, with a 236@.050" cam, .497" lift with 1.52 rockers, iron heads, 10.0:1 compression, runs great with 28 degrees timing @ idle on 87 octane, makes about 450hp. So you can go I would say 10.75:1 max and have a healthy timing curve with 91 octane.

That a ton of degrees of timing at idle what is you total advance?!??!!!? you haven't melted stuff yet???!! any ho thatnks for the advice I think I will go with about 10.1-1.

That kit is a 383 kit, it won't work as a 398 kit unless you buy different pistons.

You won't find a complete 398 kit on summit, they just aren't common enough for summit to carry them.

Email Mike Lewis of Lewis Racing Engines. He can help you out more than I can.

his email is: lewis1@mcn.org

Tell him you're from team chevelle and tell him you want to build a 398 stroker out of a 350 block, he'll help you out more than I can.

I'm running a "true" 10:1 scr with iron heads on my big block. An Isky Street Roller 290/290 advertised, 248/252 @ .050". Initial timing 21-22, total timing 39-40. Cranking compression is 190 psi.

Don't run 91 octane gas but on occasion on use 92 with zero problems.

That looks like an XE274 on a 112.
You can go FT w/vortecs and 383 and get about 10.9 cr with zero deck. Your cam is similar to mine so you'd be ok. But I have a sealed cowl hood and can only run a 160 thermostat. It will ping a little at 185 or less on 91 octane.
The EFI might make up for it. Provided you have the pataitence to not detonate it to death getting there.
I wouldn't go 398 in a 350 block for a street motor. Not enough compression ht. Not to mention,if you want that much motor, go to a 400 the first time. And your heads are too small for that anyway.

Your as listed setup as a 383 is a lot of motor.
It will make huge torque for a sbc down low. And with a 3.27 1st gear....

I'd go with a 12cc dish and near zero deck for 10.3 and you'll be fine. Might even work on 87-89.

What are your efi plans?

I plan to go with the holley c950 fuel injection with the 36Lb injectors for the 480-575hp range kit still in the process of deciding if I shoud get that kit or the 30Lb injector one with the 385-480hp, I need to estimate what I will be putting out first then accomidate with the right size fuel injection. The whole theme on my car is that it isn't like anyone else's 1972 chevelle with a 71 front end, I like to be original, ever chance I get, so I think I would like to try out this 398 it looks fun. oh and one more think I'm going with the tko600 so the first gear will be 2.84, a little bit longer for my 3.73 rear end gears so I don't have to shift like 2 seconds after I start. thanks for the info on Mike Lewis of Lewis Racing Engines I deffenetlly will be contacting him after I get back from visiting my grandparents for Christmas, Merry Christmas guy's and thanks for the input, you all have been a huge help.
Sean