[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.

[Lee]

This is the first time I've graphed these two dyno tests on top of each other, and it is rather amazing to me! I've had the data for years, just never compared it directly.

The blue line is for a 400. It has a set of SD Performance ported 6X heads, around 260cfm. The compression ratio ended up being ~8.3:1. The cam is a mild hydraulic roller, I believe around 224 @ .050 on the intake. Performer intake, Qjet, HEI, Ram Air exhaust manifolds, and a generic 2.5" exhaust system. Manual transmission.

The red line is my own 455. Unported "66" heads, compression ratio is ~8.4:1 via mini-dome KB pistons. Tri-Y headers, low restriction 3" exhaust, P4B intake, and a FAST throttle body efi system. Cam is a 222/242 HFT as mentioned in my signature. Automatic with a stock torque converter.

Both combos made several tuning passes on the dyno, and these runs are the best for each.

[Skip Fix]

Lee the 400 vs 455 I described(the RAIV 400 I sued to run against you with) that had identical top ends, cams and headers on a conservative dyno the 455 was about 30 more HP and a butt load more TQ. Not back to back but same dyno just different short blocks.

[Gator67]

I'm in the stroke it first camp, and I'd go 4.25" for sure. I ran the 462 in my '67 for 10 years with unported 670s. The car ran beautifully...really nice torquey feel on the street & interstate that you notice all the time, and not rowdy at all with a RAIV/stump puller sized cam. About 5 years ago I had the 670s ported to 250ish...this improved performance, but is something I only really notice when I really get on it.

[VCho455]

I would avoid the undocumented heads. They may have been ruined by the well meaning experimenter and you'll be the next guy looking to sell some junk heads.

Personally I would wait and do both when the funds are available.

[ponchjoe]

Originally Posted by VCho455

I would avoid the undocumented heads. They may have been ruined by the well meaning experimenter and you'll be the next guy looking to sell some junk heads.

Personally I would wait and do both when the funds are available.

I did, took the info here and decided too much of a mystery. Going to use my money ported 670s on a 462 stroker kit.
Thanks guys

[Dragncar]

Its not even questionable.
Get the cid you want, stroke it and it will be a great street engine.
If you want more power later adding a good top end is relatively easy to compared to the expense and time of a complete lower end.

[steve25]

In the chassis dyno test in post 23 you can clearly see by where the 455s peak TQ is coming in at a higher rpm then the 400 that all the added duration on the Exh lobe is flat out not needed.

[J.C.you]

If your +.040 bottom end is good with no metal in oil, good oil pressure, put on aluminum heads, intake. Upgrade your cam while at it

[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

[Skip Fix]

When I tried Rhoades they were louder than my solid flat tappet or solid roller cams!

[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]

If your wanting to run a cam you have I think you are actually better off with the 702 than the 703 for what you are doing. I would not go looking for a 703 if you have a 702 on the shelf.

[ponchjoe]

Originally Posted by Jay S

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.

Yea, the 18cc 4.160 4032 pistons.

[ponchjoe]

Originally Posted by Jay S

If your wanting to run a cam you have I think you are actually better off with the 702 than the 703 for what you are doing. I would not go looking for a 703 if you have a 702 on the shelf.

The 703 is more similar to the Bullet cam though using it?
Thanks
Advertised Duration (Int/Exh): 268/276
[email protected] (Int/Exh): 227/233
Gross Valve Lift (Int/Exh): .489/.504
LSA/CL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1600-5800

[Jay S]

Originally Posted by ponchjoe

The 703 is more similar to the Bullet cam though using it?
Thanks
Advertised Duration (Int/Exh): 268/276
[email protected] (Int/Exh): 227/233
Gross Valve Lift (Int/Exh): .489/.504
LSA/CL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1600-5800

Both the 702 and the 703 will quit making power at or before 5000 in the bigger engine. That Ultradyne 288/296 is rated at .0045” tappet, the Lunati is an advertised rating that is more of an acts like number rather than a specific tappet lift, it isn’t super easy to compare them using advertised numbers.

Lunati 703 is 273/[email protected]”

The Ultradyne I mentioned is 282/[email protected]”

The 702 is 267/[email protected]

The Voodoos have some extra assymetric's above .050” lift that older Ultradyne does not have.

With extra cubes and compression and that 288/296 Ultradyne’s LSA widened out to 112 LSA it idles pretty similarly to the 703 but out runs it everywhere, pull hard to 5500 and ifs quite a bit more pump gas friendly. Operates quiter also, since the profiles are not quite as aggressive. The LSA of the 703 is 110, it really needs to be wider to work well with the bigger cubes.

I would have preferred the 703 if you would have stuck with the small crank.