400 build. Port heads, 1.65 rockers, carb, cam?
 

I'm currently running a stock 69 400 shortblock with Edelbrock RPM 72cc round port heads, Comp XE274H cam 230/236 @0.50 110 lsa, RPM intake with Tin Indian 1" spacer, Holley 770 street avenger, Hedman 1 3/4" headers, 3" Pypes X pipe dual exhaust with tailpipes, TH400, 3.73 gear, 3000 stall converter.

I'm planning on swapping out the shortblock for a .030 over 400 with forged flat tops, ARP bolts, stock crank/rods and change to a hydraulic roller cam.

My questions are;
If I send out my heads to be ported what level claimed cfm should I be shooting for? I thought 315/325. Is there a too big for a 400?

Should I port match the intake or use a different one altogether?

Should I go bigger carb?

More converter? I don't know that I'm into much more than 3500 but???

Cam I'm thinking 230/242, 237/243 ish something in that area? 2500- 6500 range

Is there a point in 1.65 rockers?

This is a street tire shredder. It's pretty fun as it is but if I'm going to put in the labor, I'd like a little more out of it. My friends recommend a 950 or 1050 carb, 1.65 rockers, 4000-4500 stall, single plain intake, 330 cfm port work. I feel like that might just be the "everything bigger is better" theory or the fact that they have more drag focused cars in the 10's.

Anyway, thoughts on a 400 ripper? I just want to make a solid combo without a big pitfall somewhere.

Also in a 72 A-body with power brakes. Any other info let me know.

As far as head work, I'd look to a good head porter to improve flow a bit with minimum port CSA increase. Velocity is key.

Yes, run 1.65 rockers.

Pontiac 405 at 6200 RPM

https://i.imgur.com/xks8vrP.png


For intake side, these Comp QXX lobes line up close.

13479
295
241
160
.381

13480
297
243
162
.383

A good porter can get you 310-325cfm with the RA4 gasket size which isn't too big.
Personally i'd have the same porter match a RPM intake to the heads along with plenum work.
Then I'd get a cam that's mid to high 230 duration on the intake at .050 and with as much lift at the valve as possible (you can't go wrong with big lift).
These things should give you a great engine that still runs well with 3500stall converter.

I don’t know what your budget is , but for 2700 bucks in parts I would get a Butler stroker kit to make you 400 a 433 to 440 cid motor.

This will work much better with the stock port volume of your E heads , no less if you have them ported to a bigger size then the 215 CC intake runners they have now.



If you port the heads to the 315 cfm level or greater then that RPM intake is going to be a bit of a cork in the
flow system, but you can get the new motor up and running with what you have now and then see if you want to step up to a better flowing single plane manifold.

Your stock rpm intake is good to about the 550 hp level where at that point the Hp numbers will roll off down hill fast.

Since you want to go to a hydro roller I would get one such that once you add 1.65 rockers you end up with .580” lift.
This much lift is nothing for a hydro roller cam and this much lift will also have the positive effect of using more of the flow the head has to offer, and the other good side effect is due to the added flow intake port velocity will be higher for any given rpm the motor may be at which will make for a better overall driving experience.

I have ported those E heads to 340 cfm and they still made great port velocity and would take a 3200 lb car down to 9.13 in the 1/4 mile , but they need to be done right !

With porting the heads your 770 carb will still work good , especially with a single plane intake, but down the road if you still find you want a bit more top end and want to trade off some bottom end power, then a 950 cfm carb would be what I would be looking at!

Note that to run .580” lift those not so great stock E head springs will need to be changed out to a good duel spring set up, and in no springs packages with a flat wire damper should be used.

I would not even consider a 325cfm port job on a street 400. It would never run great. Unless you did everything required to make a 400ci engine get the airspeed up in the port with a CSA large enough for 325-330 cfm.
Big cam, big CR, big carb, big converter and big gear.
Ken at PPR had about the best running 400 I know of. E heads were sand rolled to 290cfm with lots of velocity.
Heavy 2nd gen ran 9.30s. It did have a Gabby Warrior intake though.
I think you are far better off to not port your heads and spend the money on a set of 4340 rods and a 4" stroke forging while you are at it. 4.25 crank if you are feeling squirrelly.
Not TRW pistons either so you can get a good ring pack.
You could save some money with a sweet custom sft cam and not worry about needle bearings flying around someday.

I would not even consider using cast rods these days, your engine is worth too much.
Forget any 1050 carb, 950 for that matter. All you need is a nice 850 DP carb and it would be on the big side on a 400.
770 Street Avengers are junk.
This right here is one of the best carb deals.https://www.jegs.com/i/Quick-Fuel/793/6-850QFT/10002/-1
Its a easy way to get a nice 850 DP. All you need is DP metering blocks, base-plate and bowls. You can even use a 750 base plate and this main body will get you a 830cfm carb.
You can always upgrade your port work later, roller cam if you want. But a solid foundation is far more important.

You need the maximum cross section area at the minimum cross section area to make maximum power at the minimum rpm and it will make good power at the maximum rpm.

What I get.

Stan

Here is another build to serve as an example only, this engine built by Dave Bisschop....

.030-over 400
6X iron heads ported to 260 cfm at .550" lift / 9.3 compression
Comp hydraulic flat tappet cam
246 @ .050" intake duration
108 LSA
0.544" lift with 1.6 ratio rocker arms
Prepped model 3310 Holley carb (800 cfm)
1 -3/4" headers

On the dyno the Torker II intake with a 1-inch carb spacer made the most peak power- 459 HP at 6250 rpm with 451 ft.lbs. torque at 5000 rpm.
But the Performer RPM intake had a broader torque curve.

Now for conversation, and food for thought.... a set of 72cc Edelbrock heads with only a mild clean up would be in the 288-300 cfm area. And would be over 10:1 compression here.

.

It would be very interesting to see a SD 290cfm/OF cam in a 400 build.

I agree with Dragncar..ditch the Avenger..800/850 Holley or a 950HP Holley would work well..

Off topic, but related to that question and a FWIW.....

Dave Bisschop states his CNC 290-295 KRE D-port heads on back-to-back dyno testing with a street/strip pump gas combination will produce as much or more more power than his CNC 315 cfm Edelbrock heads. The D-ports produce their cfm number at 0.550" valve lift and the Edelbrock heads at a slightly higher 0.600" lift. Both heads use the common FelPro 1233 intake gasket, but between the two the KRE heads would have a smaller intake runner volume.

What is not mentioned in the testing is the camshaft details nor the peak power RPM for each cylinder head. Or the compression ratio for each head. In addition the type of chamber design on the Edelbrock head is not stated, there would be a considerable difference between the older style 'bathtub' design chamber and a 'heart-shaped' chamber, that and the amount of cc's involved. Out of the box the Edelbrock 72cc head flows more than their 87cc head.


.

Even nicer to see a dyno comparison to a cam like Stan or I posted. :)

Intake dur @ .050 - within 2 degs
LSA within 1 deg
Intake centerline within 1 deg.

Maybe just coincidence... but a large book could be written on each of our tools and their legacy of success.
The why and how drove me to obsession many decades ago.
Others have a need to copy someone.

Thanks for the replies. A fair amount to think about. Most of all, if it would be worth ordering a custom cam? A friend has been trying to talk me into getting one from Bullet. I thought I would get lost but now that it's right in front of me.....

Tim Goolsby
Bullet Racing Cams
Consider UltraDyne lobes ground them, but talk with Tim.


.

Bullet is a strong choice.
Ultradyne hyd rollers look to max at .3533 lobe lift around the duration level Stan and I noted. With a bit more duration they have .3823 lobe lift, that HR19 with 169 @ .200 on the intake would be a top-end monster.

HR16 296 242 162 0.3533
HR13 302 248 168 0.3533

HR19 300 245 169 0.3823
HR20 304 249 173 0.3823


Looking through Bullet hyd roller lobes..

Maybe something around.

Intake HR292/382
292
240 @ .050
162 @ .200
.3820
CTA

---------------
Exhaust side - depending on exhaust port efficiency.
HR295/368
295
242 @ .050
160 @ .200
.3680
CRS

OR

HR304/380
304
245 @ .050
163 @ .200
.3800
CRA

That is personal preference but I'd say yes.
Also consider Mike Jones at jonescams.com

May be a bit more $ but premium stuff.



Carb consideration - aedperformance.com

Torque converter - ptcrace.com

Iceomatic, are you running a 3" or taller air filter with the RPM and spacer? Just wondering if the available room to the hood doesn't require a reduction in the air cleaner height, and if so I'd rather run at least a 3" air filter without the spacer.

If Iceomatic already has a nice set of 1.5 rockers, it would pay to have the custom cam ground with the desired lift in the lobes to save buying a new set of 1.65's. Cams in this range can easily be ground to mimic the off the shelf Old Faithful (or other cam of choice) with 1.65 rockers so the current 1.5 rockers can be retained.

Also, if this engine is going to be racking up miles, I get nervous as lifts exceed .600". Lifts can be extreme with a drag engine or an engine that is mostly a play toy without a bunch of longer trips to shows and stuff. The cam profile shown above has .700" lift and I cringe thinking of this engine blasting along for over an hour on the highway at 3,000+ RPM. My comfort level is much better with lifts in the .590-.600 range for true street driven cars.

My 78 TA has a UD 296/304 HFT in it and has plenty of bottom end and top end 1.8 rockers on intake. Hard to beat the old 288/296 231/239@ 0.050 UD cam also.

Good plans abovethat gell to the same 1-plan above:

I say; keep the 230/236 HFT and setup 1.65 on intakes, 1.5:1 on exhausts.
Tight 10" converter, and keep them headers.
800 Q-JET or 800 Holley DP or 1050 DOM. 1350 U-Joints on a steel driveshaft.


If you gotta go Roller Cam for the Street, i got no good Tech advice, just concerns for cost and reliability ( Block, Pushrods, Springs, Valvehead, maybe the Rockers need be Harland-Sharp, and expect a Fuel Octane increase ). Most all 16 Roller Lifters will be fine though.
Try an Excel tally on the Roller Cam goodies and see why HYD Flat Cams are cool.

Not sure what you are looking at..

???

I believe he was referring to the max lift noted on Stan’s info he posted.