Engine performance question

[moper]

The stock (calculated) compression ratio will be around 8.5:1 if you're lucky. Not a big deal, but if it was me I'd run that cam advanced 4* using the Summit timing set. I'd also run a 750 carb but it will run with the 600. The 4.10s will work just as well as the convertor would - I think you're fine there.

 

[mopar 3 B]

Before he up and just advances the cam 4° should he not make sure the valves will clear?

 

[david bench]

Ok did some measuring looks like 88 cc or very close in head and piston to top of block is .093 to .098 very hard to get exact with my dial indicator don't have magnetic base

 

[BSB67]

Ok did some measuring looks like 88 cc or very close in head and piston to top of block is .093 to .098 very hard to get exact with my dial indicator don't have magnetic base

Well, that is unfortunate. That is a 1.85 ish compression height piston. That means your actual compression ratio is 7.6 to 7.9:1, depending on the gasket you use.

 

[wyrmrider]

Only a couple of shelf cams
The Direct Connection 248/256 [email protected] but it's on 113 and not much lift
HUG SEH0610BL-13 473-480 lift 206-210 @.050 112lca timing is shown as -6 32 (intake closes 32 ABDC) 42 -12 -18 overlap
you could take the Howard HM2063164A lobe (or other Howard .906 lobe)
475 lift 316lobe [email protected] 206 @50 and build your own Whiplash style cam (big lobe/early closing intake) that would be like the HUG shown above with the lca squeezed down to say 108
what would I do?
go here and fill out the form anything else special use notes
http://jonescams.com/street-performance/
I've used jones 461 307lobe 256 @ .006 202 @.050 lobe but I had a true 9:1 so we spread out the lca
this lobe is asymetrical, max area .904 design but easy on the valvetrain
Mike is about the only one I know that could get what you need for an 8:1 motor
(the smaller Voodoos are chevy masters)

 

[wyrmrider]

If you are sitting at 120-130lbs per cylinder--You are 8:1 in real world...
say you want a bigger intake lobe but want to keep your intake close close to 32 ABDC to build dynamic compression
206/210 113 -6 32 42 -12 -18 olap @.050 timing depends on intake and exhaust center-lines shown is nominal
210/216 108 -1 31 42 -6 -7 olap
216-220 108 2 34 48 -4 -2 olap
220 224 107 5 35 45 -1 +4 olap
What I can't tell you is what the seat timing is- .050 is way too far away to really tell- just to give you an idea
and I can't tell you what seat intake close you want with 8:1 compression
Jones has a computer program that will get you as close optimized as possible
you have to consider rod ratio, stroke, mass and velocity of the intake charge (as it changes as intake closes) (get as much in as possible then shut the door at the right time) headers and mufflers, etc

 

[JimKueneman]

My 318 has similar compression/cam/etc and I get low 80% volumetric efficiency (VE) at lower RPM and push into the mid 90% VE around 3500 RPM. If you do the math for the 383 at 100% VE you need about a 750 CFM to feed it. At 95% about 700CFM and 83% 650CFM in the perfect world. There are lots of tuners and articles about how this calculation is not really accurate and you should use WOT vacuum as your gauge. So in the perfect world you will likely be a little under on the carb but will you notice it? Also consider if you plan I running it hard. These number are for 6500 RPM. If you don't plan to run the crap out of it then at 5000 RPM the numbers are in the 600 CFM range from the calculation.