396 Chevy combo......

Stocker Fan · 05-30-2007, 10:55 PM

guys, ineed a quick history lesson. what is the difference between the 3 different hp combos on the 396? i see the 375 seems to be hit the worst, why? is it that much better?

thanks to all,

wade owens #3913
66 chevelle
under construction stocker

Alan Roehrich · 05-31-2007, 01:52 AM

The 325 and 350 HP engines have oval port heads with smaller intake ports and valves, less compression, and cam (hydraulic instead of solid, too).

The 375 is getting hit for two reasons. It has a lot of potential, and that potential is being exploited, by a lot of people.

It has the same heads, cam, intake, and carburetor as a 427-425, with 30 less cubic inches to feed. So it rev's higher and makes more HP per cubic inch, common when you have engines restricted by various rules.

The 396-375 is also very common, a lot of people run them, in everything, Chevelles, Novas, and Camaros, to name a few. They fit well in A, B, and C, in both the Camaro and the Nova.

Alan Roehrich

Bring "AA" classes to NHRA Stock Eliminator!

Stocker Fan · 06-01-2007, 12:12 PM

thanks alan, i appreciate you taking time to comment.

wade o

Adger Smith · 06-03-2007, 06:07 PM

Stocker Fan,
The way the 375 HP guys are flying I wouldn't be surprised if they don't get some added HP at mid season. There have already been several runs much quicker than the 1.15 trigger point. In my opinion, Any of those combos you ask about can be made workable. It's only a matter of how fast you want to go & how much do you want to spend.

Adger Smith

06-04-2007, 07:35 PM

So is there any advantage or disadvantage over the 396 versus the 402.

Thanks, Alan Warman L/SA 4103

Alan Roehrich · 06-04-2007, 08:04 PM

I don't know that there is really a lot of difference, I'd say Keith Lynch is as qualified to answer that as anyone, since last time I talked to him, he was running a 402-375, and Schroeder was running a 396-375, Keith is tuning both. They're both REAL fast, and can run A or B.

Alan Roehrich

Bring "AA" classes to NHRA Stock Eliminator!

Adger Smith · 06-05-2007, 12:54 AM

I think the 402 might get a slightly smaller chamber & seems there is something about the ex valve.can't remember it all. might have just been with the 401 head You can check the blueprint specs to see.

Adger Smith

Bryan Broaddus · 06-05-2007, 12:56 AM

402 gets a bigger dome and the exhaust valve is a 1.88
396 is the 1.84 valve

Adger Smith · 06-05-2007, 11:55 AM

Just checked the NHRA specs (1969 396 vs 1970 402) & it looks like the 401 alum. head gets a tighter chamber in both the 402 & the 396 @ 103.3 On the other hand the iron 396 is @ 104.9 vs the 402 iron @ 106.9.
Dome on the 396 is 40.05 @ .361 ht Vs the 402 with 39.53 @ .344 ht. That was probably done to equalize the difference in bore vol.(CC).
The 396 ex is 1.845, in alum & 1.725 in iron vs the 402 @ 1.885 in iron and alum.
It also looks like the 402 gets to use a better manifold than the original pancake version. I'm not real familar with the manifols esp. the 3967474, but it seems like the 402 & 396 would be at least equal in that area.
You need to check the NHRA Classification guide for the HP. There are some differences between bodies & stick vs auto in the 402 vs 396.
good luck hope this helped
DISCLAIMER: all numbers are form NHRA Tech Specs. I'm not responsible for type-o's or numbers that are transposed. I am responsible for my opinions.

Adger Smith

Alan Roehrich · 06-05-2007, 01:29 PM

I haven't looked at ALL of the 396 and 402 engines, but supposedly any engine that can run the "163" intake is allowed to run the new "359" intake. Most of the big HP (375HP 396, 425HP 427 etc.) big block cars are running the 359 intake now, at least the ones I've seen.

Alan Roehrich

Bring "AA" classes to NHRA Stock Eliminator!

05-30-2007, 10:55 PM	#1
Stocker Fan Junior Member Join Date: Oct 2006 Posts: 11 Likes: 0 Liked 0 Times in 0 Posts	396 Chevy combo...... guys, ineed a quick history lesson. what is the difference between the 3 different hp combos on the 396? i see the 375 seems to be hit the worst, why? is it that much better? thanks to all, wade owens #3913 66 chevelle under construction stocker

05-31-2007, 01:52 AM	#2
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,916 Likes: 997 Liked 1,046 Times in 276 Posts	The 325 and 350 HP engines have oval port heads with smaller intake ports and valves, less compression, and cam (hydraulic instead of solid, too). The 375 is getting hit for two reasons. It has a lot of potential, and that potential is being exploited, by a lot of people. It has the same heads, cam, intake, and carburetor as a 427-425, with 30 less cubic inches to feed. So it rev's higher and makes more HP per cubic inch, common when you have engines restricted by various rules. The 396-375 is also very common, a lot of people run them, in everything, Chevelles, Novas, and Camaros, to name a few. They fit well in A, B, and C, in both the Camaro and the Nova. Alan Roehrich Bring "AA" classes to NHRA Stock Eliminator! __________________ Alan Roehrich 212A G/S

06-03-2007, 06:07 PM	#4
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,351 Likes: 435 Liked 678 Times in 262 Posts	Stocker Fan, The way the 375 HP guys are flying I wouldn't be surprised if they don't get some added HP at mid season. There have already been several runs much quicker than the 1.15 trigger point. In my opinion, Any of those combos you ask about can be made workable. It's only a matter of how fast you want to go & how much do you want to spend. Adger Smith __________________ Adger Smith (Former SS)

06-04-2007, 08:04 PM	#6
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,916 Likes: 997 Liked 1,046 Times in 276 Posts	I don't know that there is really a lot of difference, I'd say Keith Lynch is as qualified to answer that as anyone, since last time I talked to him, he was running a 402-375, and Schroeder was running a 396-375, Keith is tuning both. They're both REAL fast, and can run A or B. Alan Roehrich Bring "AA" classes to NHRA Stock Eliminator! __________________ Alan Roehrich 212A G/S

06-05-2007, 12:54 AM	#7
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,351 Likes: 435 Liked 678 Times in 262 Posts	I think the 402 might get a slightly smaller chamber & seems there is something about the ex valve.can't remember it all. might have just been with the 401 head You can check the blueprint specs to see. Adger Smith __________________ Adger Smith (Former SS)

06-01-2007, 12:12 PM	#3
Stocker Fan Junior Member Join Date: Oct 2006 Posts: 11 Likes: 0 Liked 0 Times in 0 Posts	thanks alan, i appreciate you taking time to comment. wade o

06-04-2007, 07:35 PM	#5
MaxZRX Guest Posts: n/a	So is there any advantage or disadvantage over the 396 versus the 402. Thanks, Alan Warman L/SA 4103

06-05-2007, 12:56 AM	#8
Bryan Broaddus Member Join Date: Jun 2002 Posts: 100 Likes: 1 Liked 18 Times in 3 Posts	402 gets a bigger dome and the exhaust valve is a 1.88 396 is the 1.84 valve __________________ Bryan Broaddus 7568 STK ,SS

06-05-2007, 11:55 AM	#9
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,351 Likes: 435 Liked 678 Times in 262 Posts	Just checked the NHRA specs (1969 396 vs 1970 402) & it looks like the 401 alum. head gets a tighter chamber in both the 402 & the 396 @ 103.3 On the other hand the iron 396 is @ 104.9 vs the 402 iron @ 106.9. Dome on the 396 is 40.05 @ .361 ht Vs the 402 with 39.53 @ .344 ht. That was probably done to equalize the difference in bore vol.(CC). The 396 ex is 1.845, in alum & 1.725 in iron vs the 402 @ 1.885 in iron and alum. It also looks like the 402 gets to use a better manifold than the original pancake version. I'm not real familar with the manifols esp. the 3967474, but it seems like the 402 & 396 would be at least equal in that area. You need to check the NHRA Classification guide for the HP. There are some differences between bodies & stick vs auto in the 402 vs 396. good luck hope this helped DISCLAIMER: all numbers are form NHRA Tech Specs. I'm not responsible for type-o's or numbers that are transposed. I am responsible for my opinions. Adger Smith __________________ Adger Smith (Former SS)

06-05-2007, 01:29 PM	#10
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,916 Likes: 997 Liked 1,046 Times in 276 Posts	I haven't looked at ALL of the 396 and 402 engines, but supposedly any engine that can run the "163" intake is allowed to run the new "359" intake. Most of the big HP (375HP 396, 425HP 427 etc.) big block cars are running the 359 intake now, at least the ones I've seen. Alan Roehrich Bring "AA" classes to NHRA Stock Eliminator! __________________ Alan Roehrich 212A G/S