[rohrt]

Originally Posted by ponchjoe

Hey all,

I am going back and forth on taking my .040 400 to 435 with a 4” crank or just going with the 408 and spending money on ported heads.
The car is a 67 LeMans that will be street and highway only with an OD and 3.55 gears. I have 670 non ported heads that need everything and I have a line on some 670s that are ported and ready to go with no flow numbers unfortunately.
For this street only application, is the additional cubes a benefit over the ported heads or vice versa?

f

I'm considering a very similar build. 428 with 670 heads for street and highway as well. I was considering sending the heads off for chamber work and leave them non ported. My thought was to keep the port velocity high at lower RPM cruising. The comments above have me a bit discouraged. Except for i82much's comment. That hilarious LOL

[ponchjoe]

Originally Posted by rohrt

f

I'm considering a very similar build. 428 with 670 heads for street and highway as well. I was considering sending the heads off for chamber work and leave them non ported. My thought was to keep the port velocity high at lower RPM cruising. The comments above have me a bit discouraged. Except for i82much's comment. That hilarious LOL

Well, I got a heck of a deal from Clegg Engine Sales on an Eagle 462 stroker kit with custom DSS pistons so CID wins! Now I need help with cam choice as I was going to use my 702 VOODOO and still may for driveability. Look for “Another Cam Choice” thread from me coming soon.
They were very helpful compared to other suppliers and I highly recommend them.

[Gary H]

Originally Posted by ponchjoe

Well, I got a heck of a deal from Clegg Engine Sales on an Eagle 462 stroker kit with custom DSS pistons so CID wins! Now I need help with cam choice as I was going to use my 702 VOODOO and still may for driveability. Look for “Another Cam Choice” thread from me coming soon.
They were very helpful compared to other suppliers and I highly recommend them.

Good luck getting any Pontiac cam from Lunati. I think they're unattainable!

[ponchjoe]

Originally Posted by Gary H

Good luck getting any Pontiac cam from Lunati. I think they're unattainable!

I have the 702 and a line on a 703. Edelbrock swallowed up Comp and Lunati and shed Pontiac from Lunati. I hope they create some new Comp cams with the Lunati lobes. May look at the 60243 Crower too, I’ve used it before

[Jay S]

Originally Posted by ponchjoe

I have the 702 and a line on a 703. Edelbrock swallowed up Comp and Lunati and shed Pontiac from Lunati. I hope they create some new Comp cams with the Lunati lobes. May look at the 60243 Crower too, I’ve used it before

If the plan is to use little cams like those there is no reason to put a much bigger crank in the engine. 4” is ok, but with those cams it won’t run a lot better than the 3.75”. You”ll end up dropping the compression more on the bigger cranks to keep the engine happy on pump gas. It offsets a lot of the gains with the bigger crank.

[ponchjoe]

Originally Posted by Jay S

If the plan is to use little cams like those there is no reason to put a much bigger crank in the engine. 4” is ok, but with those cams it won’t run a lot better than the 3.75”. You”ll end up dropping the compression more on the bigger cranks to keep the engine happy on pump gas. It offsets a lot of the gains with the bigger crank.

Jay, as stated a few posts ago it is getting the 4.25 stroke kit and is a cruiser/highway car with AC and an OD not a race car. Why wouldn’t the 703 be a good choice and what do recommends, the RA4 cam and noisy Rhodes?
Thanks

[Jay S]

Originally Posted by ponchjoe

Jay, as stated a few posts ago it is getting the 4.25 stroke kit and is a cruiser/highway car with AC and an OD not a race car. Why wouldn’t the 703 be a good choice and what do recommends, the RA4 cam and noisy Rhodes?
Thanks

AH. I see now you have the stroker kit coming. Which DSS pistons did you get? 18 cc dish with 670s?

I would suggest a Bullet Ultradyne 288/296
231/239 @.050” a 112 LSA
And use regular lifters.

[Jay S]

9.68 would be higher than those smaller cams would want.

I ran the numbers with a 28cc and came up with 9.25, but I added in 1cc for cylinder scallops on to the 72 cc heads. Ball park guess yet.

[ponchjoe]

Originally Posted by Jay S

9.68 would be higher than those smaller cams would want.

I ran the numbers with a 28cc and came up with 9.25, but I added in 1cc for cylinder scallops on to the 72 cc heads. Ball park guess yet.

Well, after a conversation we will probably go to custom Autotechs as DSS told them the 28cc were not something that had a part number.
Here’s what we came up with from AUTOTECH

I’m 4.160 bore.

[chiphead]

I see a few flaws with this approach to selecting pistons.

Finished bore. Do you know exactly what your finished bore is? How are you setting bore clearance? Auto tech can set the skirt clearance if you know the finished bore down to .001

Deck height. Don't order pistons without knowing deck. Otherwise you'll have to deck the block a bunch afterwards. Auto tech lets you set the pin height if you know the number to use.

Chamber size. Do you even know the finished chamber size of your 670s? Never order pistons without knowing finished chamber. Any head work is going to change the chamber size.

Future growth. With a big piston dish, how are you going to raise compression if you swap to aluminum heads?

What ring pack? Metric or 1/16?

What ring pack placement? How deep are the cyl reliefs? Don't hang a ring on the scallops!

Not trying to be difficult, but you can paint yourself into a nasty corner with piston selection.

[ponchjoe]

Originally Posted by Jay S

9.68 would be higher than those smaller cams would want.

I ran the numbers with a 28cc and came up with 9.25, but I added in 1cc for cylinder scallops on to the 72 cc heads. Ball park guess yet.

Jay, I’d love to talk to you sometime soon about this build if you are willing.

Joe

[Jay S]

Originally Posted by ponchjoe

Jay, I’d love to talk to you sometime soon about this build if you are willing.

Joe

That would be fine.
402.682.1663