Thread: Hot Street 396 build, dyno numbers?

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Just enter the flow numbers under the cylinder heads / custom port flow.

Best list out there I know of...............


http://racingfeed.com/downloads/chevy_flow_data.pdf

This was one of my first port jobs, the exhaust didn't turn out quite as well as I'd hoped for but I did it without a flowbench. This flowtest was taken at GrommRacingHeads.

intake/exhaust flow @ 28 inches
.100 lift- 67/63.39
.200 lift- 153/108
.300 lift- 213/130
.400 lift- 252/149
.500 lift- 271/165

Closed chamber 96.4cc
255cc intake runner

Sounds like a good motor to me,low rpm power means less engine wear and every time you shift it will drop down into to torque band. 500 + torque is good stuff
Keep in mind thats only a estimate from one simulation,real world results may differ
I am with Pat,I thought less on torque, just from other hp to torque build specs I have seen.Maybe the HP is close to 450 + ? Which would mean less low rpm torque.
From the page Viking posted it looks like about 250-260 on the inkake about 170-185 exaust are what flow numbers it takes to make close to 500hp.Your pretty close on the exaust ,maybe some ratio on the exaust rocker ? ...Or a split duration cam that is going to make up for the exaust and take advantage of those good intake numbers.

Originally Posted by shawnlee28

Sounds like a good motor to me,low rpm power means less engine wear and every time you shift it will drop down into to torque band. 500 + torque is good stuff
Keep in mind thats only a estimate from one simulation,real world results may differ
I am with Pat,I thought less on torque, just from other hp to torque build specs I have seen.Maybe the HP is close to 450 + ? Which would mean less low rpm torque.
From the page Viking posted it looks like about 250-260 on the inkake about 170-185 exaust are what flow numbers it takes to make close to 500hp.Your pretty close on the exaust ,maybe some ratio on the exaust rocker ? ...Or a split duration cam that is going to make up for the exaust and take advantage of those good intake numbers.

Ya, I was thinking about running 1.8's on the exhaust to see if it might help power. But I want to run this cam for now. If I really wanted to, I could have ported the exhaust a little more after I got the heads flowtested but I guess I got lazy.

I did do a desktop dyno before and put all my specs in, except it was a regular version of desktop dyno. It didn't have the headflow feature. Made 480 horsepower/490 torque. That sounded about right to me. I wouldn't think a 240 duration at .050 would make 500+ torque and only 415 horsepower. But I think I will be satisfied with 450 horsepower, considering I built the whole engine for about $4000. That was including the $500 March serpentine pulley kit. Can you say budget big block? I'm sure Pat can probably match that though. The more work you do yourself the cheaper it gets.

Originally Posted by 69elko

Ya, I was thinking about running 1.8's on the exhaust to see if it might help power. But I want to run this cam for now. If I really wanted to, I could have ported the exhaust a little more after I got the heads flowtested but I guess I got lazy.

I did do a desktop dyno before and put all my specs in, except it was a regular version of desktop dyno. It didn't have the headflow feature. Made 480 horsepower/490 torque. That sounded about right to me. I wouldn't think a 240 duration at .050 would make 500+ torque and only 415 horsepower. But I think I will be satisfied with 450 horsepower, considering I built the whole engine for about $4000. That was including the $500 March serpentine pulley kit. Can you say budget big block? I'm sure Pat can probably match that though. The more work you do yourself the cheaper it gets.

I am sorry I miss read your post about the mech. cam
At 450 hp that is more than 1.1 hp per cubic inch and that sounds very good when using stock heads.
I like the March products but they are very slow.
Over a month a go I ordered a serpentine pulley kit for a customer and he is still waiting on it.
Now today I hear they are shipping everything but the bottom crank pulley.
They say I should get that in another few weeks.
What can you do??

Originally Posted by erik erikson

I am sorry I miss read your post about the mech. cam
At 450 hp that is more than 1.1 hp per cubic inch and that sounds very good when using stock heads.
I like the March products but they are very slow.
Over a month a go I ordered a serpentine pulley kit for a customer and he is still waiting on it.
Now today I hear they are shipping everything but the bottom crank pulley.
They say I should get that in another few weeks.
What can you do??

Yeah when I ordered the kit from Summit they took a little longer than usual. Wasn't a month, but was about a week. Was missing the allen screws for the alternator pulley cap.

Well, maybe I'm wrong. I guess I had higher hopes for this engine. There wasn't any other head I could use without the use of a massive dome piston which they don't make for a 396. All aftermarket heads are in the 113cc-119cc chamber range and would give me 8-9 compression with my 17cc dome piston. After all the hassle I've been through, I think I'm gonna build a 468 as my next engine.

Originally Posted by 69elko

Yeah when I ordered the kit from Summit they took a little longer than usual. Wasn't a month, but was about a week. Was missing the allen screws for the alternator pulley cap.

Well, maybe I'm wrong. I guess I had higher hopes for this engine. There wasn't any other head I could use without the use of a massive dome piston which they don't make for a 396. All aftermarket heads are in the 113cc-119cc chamber range and would give me 8-9 compression with my 17cc dome piston. After all the hassle I've been through, I think I'm gonna build a 468 as my next engine.

just go to a 496 they are not that much more and from there rigth to 565

Originally Posted by 69elko

This was one of my first port jobs, the exhaust didn't turn out quite as well as I'd hoped for but I did it without a flowbench. This flowtest was taken at GrommRacingHeads.

intake/exhaust flow @ 28 inches
.100 lift- 67/63.39
.200 lift- 153/108
.300 lift- 213/130
.400 lift- 252/149
.500 lift- 271/165

Closed chamber 96.4cc
255cc intake runner

The heads I used in DD have higher flow than what you posted .............

Kitz