[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]

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

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.

[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.

[chiphead]

Originally Posted by ponchjoe

Yea, the 18cc 4.160 4032 pistons.

Did you measure final chamber size before you ordered pistons? I made that mistake on my original 400. Thought I had 72cc 670s, so I ordered 20 cc dish pistons for 9.2 compression with 3.75 stroke. Imagine my surprise years later when I actually cc'd the heads and got 77ccs! This was back in 2002-03 when I was led into the lower compression ratios and XE cams way of thinking.

For your 4.25 stroker motor, I ran the numbers. With 18CC dish, are you expecting 10.42 compression with 72cc (nominal) heads? That's too high for those 670s. That's perfect if you're going aluminum.

With high compression, you need at least a 228* intake lobe and 112-114LSA.

[Jay S]

The 28 cc dish DSS was a custom piston because of the dish change. Those pistons are in an engine in my area. Autotec are nice pistons.

Icon makes a 4.25” stroker piston with a 30cc dish. I think it uses a 6.635” rod instead of a 6.8. Ic981 is the part#.