[Dryseals]

OK I know this has probably been hashed around a lot but the search did not turn up what I was looking for. I bought a 66 Tempest a while back and was going to drop a 383 Chevy in it, but had an epiphany the other day and just brought home a 76 400 block. I’ve been building Chevies for years and now I need some help.
So my question is, I want to use the Edelbrock heads as a form of weight savings and allow me to go to the higher compressions with out a lot of problems. Are the port velocities of these heads prone to a high revving engine or will they work good as a street engine revving top the 5500 to 6K mark. Can they still produce everyday driving torque at the lower RPMs?

[Dryseals]

OK I know this has probably been hashed around a lot but the search did not turn up what I was looking for. I bought a 66 Tempest a while back and was going to drop a 383 Chevy in it, but had an epiphany the other day and just brought home a 76 400 block. I’ve been building Chevies for years and now I need some help.
So my question is, I want to use the Edelbrock heads as a form of weight savings and allow me to go to the higher compressions with out a lot of problems. Are the port velocities of these heads prone to a high revving engine or will they work good as a street engine revving top the 5500 to 6K mark. Can they still produce everyday driving torque at the lower RPMs?

[AIR RAM]

To keep your compression Ratio down go with the 84cc heads. With a flat top piston you will be in the ball park of 9.5:1-10:1. with the 72cc head you will be about 2 full points higher. They flow real well out of the box and offer great street power all the way up to 6000RPM's (Thats as high as I have reved them) and Im sure they have more breathing capability to rev higher. If you have the money I think they are a great buy.

Im sure your 400 will make you a PONTIAC man when your done with it. Dont forget to spend some money on the rear suspension, youll need it to put all of that torque to the ground. [img]/infopop/emoticons/icon_biggrin.gif[/img]

SPEED SAFE, AIR RAM

Im putting together a .040 455 with Edelbrock heads (72cc), Eagle Rods, FLAT top J&E Pistons for 12:1, Harland sharp roller Rockers, Fluidampner, Edelbrock Performer RPM intake, and 750 Demon Carb. "GOT TRACTION"

[slowbird]

They should be just fine as long as you pick a cam to work with the combo. I would go with 72cc head for the compression. We run 75cc iron heads on our 400 and have no problems so the e-heads should be fine as well.

[Blackcat]

A Pontiac will give you more Torque than your tires can handle! Juat a basic rebuild with an HO Cam with Low compression is more than enough!
Where in Texas are you from?
What most of us need to know is just what you want out of the car so We can better help you! [img]/infopop/emoticons/icon_wink.gif[/img]

Usually I'm found working on my Pontiac. If you want to find me Look for the white picket fence and all the old Pontiacs parked outside. And the half dissembled engine sprawled all over the driveway!

[Dryseals]

I'm down here in Orange, TX LA border on the Gulf coast. I'm re-creating the past with a little more kick. I used to have a 67 GTO 400, M22 and 3.90 rear with an Offy dual port and believe it or not a Holley 450 economaster. Unbelieveable out of the hole but ran out of carb around 4800 RPM. I sold it many years back and kick myself every day for doing so. So I've been a Pontiac man for many years, just didn't have one.

I'm building this to be a semi daily driver, I say semi because I have 2 extended cab trucks, a street truck, a Corvette an MGB and now the Tempest. So I will not rely on this for daily driving but it will see its fair share of street use with an occasional trip to the local track.

I've been looking at cams in the 220s range for intake and 230s for exhaust @ .05 or longer durations ,this is not set in stone, it depends on what will match with what. This is why I’m looking to the aluminium heads, to up compression for the longer duration.

I guess the main thing is, I don't want to mess with the older heads if I can help it. Spent enough money on Chevy heads to learn that if this is what I want/need then just get it and be done with it

And believe me I’m open to suggestions.

[Cliff R]

Aside from being heavier, a well prepared set of #12's, 13's, 62's or 16's will work fine on the 400 engine. With carefull preparation and parts selection you can manage 10 to 1 CR on pump fuel with the iron heads. Have a lot of these engines in use. The early big valve iron heads will support the 400 engine to the redline of the shortblock with correct cam selection. Certainly a lot less expensive than Edelbrock heads.

To more directly answer your question on head flow, the Pontiac "D" port heads are very well suited to making strong mid-range power. Never any need to turn a street driven Pontiac mill to high rpm to make respectable power. Installing the much larger port Edelbrock heads will not in and of themselves increase performance. In most cases the shift point will have to be increased and larger cam installed to see any improvements. This is usually followed by selecting drivtrain parts more suitable for the shift in power to higher rpm's.

Glad to see you are considering a Pontiac engine over the SBC! Most folks go right past the 400's these days in search for the big torque of the 455. The 400's are great engines and the type of power they produce is much easier to use in a street driven car. Have some very successful combinations in use, don't hesitate to ask for specifics.......Cliff

[fordguy57]

SAY CLIFF, SINCE YOU SAY NOT TO HESITATE TO ASK FOR SPECIFICS, THOUGHT I WOULD JUMP IN HERE ALSO..
I ALSO JUST DRAGGED HOME A TIRED 75 (POSIBLY 74..) 400 ENGINE TO USE IN A 65 LEMANS CONVERTIBLE WITH A 4 SPEED. THE REAR GEAR RATIO HAS YET TO BE DETERMINED (HAS AUTO TRANS NOW, AND AM CONVERTING..). THIS ENGINE HAS 4X HEADS APPROX 1.96 INTAKE VALVE. AM TOLD THAT 6X #4 HEADS ARE BETTER CHOICE CUZ OF 2.11 VALVES. YOUR OPINION ON WHICH HEADS TO USE? HOW ABOUT CAM? I WAS THINKING OF SOMETHING LIKE THE 268H EXTREME ENERGY CAM. THOSE TOP OUT AROUND 5200-5400 RPM I UNDERSTAND. PROBABLY PUT IN ROLLER ROCKERS ALSO, DON'T KNOW WHAT KIND (RATIO SUGGESTIONS?), BUT BEEN NOTING SOME CONCERNS ON STATED RATIOS OUT THERE..PLAN ON USING WEIAND ACTION PLUS INTAKE PROBABLY ALONG WITH 750 HOLLEY VAC SECONDARY. FLAWS IN COMBO? SHORTCOMINGS? FURTHER SUGGESTIONS/ OPINIONS? THANKS, MIKE H

[Cliff R]

Mike H, the 6X-4's would be a better choice than the 4X, but neither will build enough compression for fantastic performance. With a 92cc chamber your only at 8.2 to 1 in the 400 engine. You will need at least 9.5 if not 10 to 1 for the XE268 cam. I am currently testing an XE268 cam in a 400 with ported #16's. I am not initially impressed with this cam, idle is smooth and not making nearly the power expected.

You are at the crossroads when building a 400 for decent performance. You can cut a set of 6X-4 heads to death and get just over 9 to 1 or prepare a set of 13's or 62's and be right at 10 to 1. My vote is to use the high compression heads. This opens up options for cam selection and with carefull preparation, parts selection and tuning you can manage pump fuel without problems. Higher compression engines make more power at all rpm. Difficult to take a low compression engine and jam enough air into them for sparkling low and mid-range power and still make great top end. To keep the cam small enough for good low speed power, you will hit a brick wall before 5000rpm. If you cam it up for strong top end power, its a turd out of the gate.

We have came up with a very potent combination for daily driven cars using the early high compression heads and pump fuel. 400 block, zero deck, Crower 60916 cam, HS 1.65 rockers, RPM or ported stock intake, mild porting on heads, 800cfm carb, 4 tube headers and free flowing exhaust system. This combo will provide a decent idle and enough vacuum for PB, strong power from right off idle with great top end power to at least 5500rpm. Will propell a mostly stock GTO to low 13's in street trim, well into the 12's with slicks.

There are certainly other successful combinations out there, have spend considerable time with this one both on the dyno and street/track testing. Best of all it manages pump fuel without problems and no tendency whatsoever to run hot/overheat or detonate....hope this helps some....Cliff

[slowbird]

Cliff what is the cam specs on that cam in the 400 and what did it dyno at? Do you have any experience with the e-heads on a street driven 400?

[Cliff R]

The specs on the 60916 are 221/229, .455/.470, 112. One was installed (with HS 1.65 rockers) in a very basic 400 at 10 to 1 CR and UNPORTED heads (#62's) it made 417hp/453ftlbs on KRE's dyno. Have been building them with ported heads, filled crossovers, RPM intake and 800cfm q-jet, very effective combination.....Cliff

[Cliff R]

Ooops! Forgot to comment on E heads. Have not installed any here on 400 engines. The "D" port heads (well prepared) have sufficient runner capacity for street driven 400cid engines. See no need for any more airflow potential. We typically set up street driven 400 engines for no more than 6000rpm and shoot for a shift point of 5500rpm. This means we are looking for a lot of mid-range power, the smaller runners in the "D" port heads are near perfect for this. Not sure if you'd see any benefits using larger runners except on top end. The other stumbling block is the cost of the heads and having to buy expensive headers to use them. We can throw a lot of money into a set of "D" ports and never come close to the cost of the conversion......Cliff

[Lee]

DrySeals,

Hey, I'm about an hour to the west of you, in Baytown. Send me an email if you need an local (relatively) contacts.

Lee Atkinson
67bird@symet.net

[Skip Fix]

My RAIV 400 used a 231/239@0.050 cam and the HP peak was 6200 and ran my A/C fine. The E heads should be similar, they'll like more lift so I'd use some 1.65 rockers and clearance the heads for them. Enough bottom end if you gear it right. It used to run with a alot of 455s.

The head debate is one that's been on here alot. I'm sure I'll get flamed but the die hard iron head guys.I've run both iron heads and E heads. The E heads are cheaper than finding some RAIVs and flow even better and already have hardened exhaust seats for unleaded. if you break one its not a rare head to replace.

My machinist who has ported alot of Pontiac heads built a similar 455 to the one I built with the RAIV heads with ported 6Xs.It was 80 hp less, so yes the air flow can help. We had dropped the compression some on the RAIV 455 with the pistons and the 6Xs were milled so a little closer on the compression ratios than it would appear.

If you don't have D port headers "good" d ports will cost you also.Hedman has a 1 3/4 set that fit GTOs and F bodies(loosely on the F bodies) that woul dbe ideal.

The E heads are around $1600-1700 complete. 6X-4s I'm currently building: $80 at the junk yard $ 30 for hot tanking and magging,new valves $160, springs and retainers $150, 3 angle valve job $95. milling $50. So almost $700 for stock heads.Throw some porting in at a place like SD Performance and they are around $1200 complete. D ports can sure do the job for a good street motor as Cliff said but so can the E heads and you have room to go faster if you want.

On a 400 I would definitely NOT think of using a single plane intake. That wil kill the bottom end for very little top end pick up.I'd look at a performer RPM.