[Stripes]

I have a 69 FB that had a 1977 pontiac 350, 7.6 to 1. 100 and something horsepower engine swapped in. (No idea why that was done)

It's all stock and so underpowered. I'm eventually going to swap it out. But in the interim, would a cam change wake it up a little? I was thinking an 068 cam? Or is that even too much for a stock 350? The car does have a 4 speed muncie and a 3:42 rear gear. Hopeless?

[b-man]

With 7.6:1 compression I’d recommend the 066 cam.

The 066 cam was used in the 7.6:1 185 hp 400 engines powering the ‘76 T/A coupled to a TH350 and a 2.41 posi rear. Should do okay in your low compression 350 engine with the 4-speed stick and 3.42 gears.

[ponyakr]

256 Voodoo

https://www.lunatipower.com/voodoo-h...8-256-262.html

https://www.ebay.com/p/192751619?gcl...nid=6470549460

This might be my 2nd choice.

https://www.summitracing.com/parts/h...w/make/pontiac

This might be my 3rd choice.

https://www.summitracing.com/parts/sum-2800

https://www.ebay.com/itm/Pontiac-V8-...AAAOSwmrlU0mJ9

The 066 was used in the '74 GTO 350.

http://www.wallaceracing.com/enginesearch4.htm

If you wanna go with an 066, the Melling SPC-4 is supposed to be pretty close. Might get by with your stock springs, since the lift is so low. Or, the stock springs listed above will work.

https://www.ebay.com/itm/Engine-Cams....c100005.m1851

I went with Jegs lifters because they were the cheapest USA made lifters I could find. I think those I got were made by Delphi. The guy at Summit couldn't say where the Summit lifters were made.

https://www.jegs.com/i/JEGS/555/20702/10002/-1

[ponyakr]

As always, Summit has their Beat-a-Price deal, on stuff they have in stock.

https://help.summitracing.com/app/an...tail/a_id/558?

https://www.summitracing.com/parts/mel-spc-4

But keep in mind, they now charge tax. Or at least they now charge me tax. Amazon has also started charging me tax. Some Amazon sellers don't. Some online vendors do not yet charge tax. This can cost you quite a few extra bucks, on higher priced items. Can change where you find the best total price of an item you want.

[steve25]

If you want to wake it up then you need more compression before you stuff in a bigger Cam that will only lower the cylinder pressure.

If you do anything to try and as you say wake it up you want a Cam with a good amount more lift to pick up port velocity which will add both throttle responce and HP.

The 068 Cam has the same lift your Cam has now and the only thing it will serve to do is to allow the motor to make a greater level of power above 4000 rpm while reducing the power you now have below that 4000 rpm point.

Your .406" valve lift you have now needs to go as close as you can get to .470" lift so you will need to change the valve springs which by the way you should do anyway even if you where using the 068 Cam.

The 256/262 Lunati looks like a good pick if you have atleast 3.23 rear gears.

[steve25]

If you want to wake it up then you need more compression before you stuff in a bigger Cam as that will only lower the cylinder pressure that you do not have enough of as it stands now!

If you do anything to try and as you say wake it up you want a Cam with a good amount more lift to pick up port velocity which will add both throttle responce and HP.

The 068 Cam has the same lift your Cam has now and the only thing it will serve to do is to allow the motor to make a greater level of power above 4000 rpm while reducing the power you now have below that 4000 rpm point.

Your .406" valve lift you have now needs to go as close as you can get to .470" lift so you will need to change the valve springs which by the way you should do anyway even if you where using the 068 Cam.

The 256/262 Lunati looks like a good pick if you have atleast 3.23 rear gears.

[slowbird]

We ran an old UltraDyne cam in the 350 when we first got our 73 Ventura. Cam was 216-221 with .460ish lift (been almost 20yrs so not 100% sure on specs) but it ran decent. Engine had 120,000 miles it and it wasn't long before one of the cast pistons let go.

[ponyakr]

"...The 256/262 Lunati looks like a good pick if you have atleast 3.23 rear gears..."


"...The car does have a 4 speed muncie and a 3:42 rear gear..."

[Stan Weiss]

Originally Posted by slowbird

We ran an old UltraDyne cam in the 350 when we first got our 73 Ventura. Cam was 216-221 with .460ish lift (been almost 20yrs so not 100% sure on specs) but it ran decent. Engine had 120,000 miles it and it wasn't long before one of the cast pistons let go.

I would guess the H3 and H4 lobes.



Master___Adv_____0.050_____0.200_____Lobe
Number_Duration_Duration_Duration____Lift_____104_ ____106_____108_____110_____1.5_____1.6_____1.7

Hydraulic_Profiles_Adv_=_.0045"
H13______246______193_______100_____0.2620___0.030 ___0.025___0.021___0.017___0.393___0.419___0.445
H7_______254______199_______106_____0.2673___0.037 ___0.032___0.026___0.021___0.401___0.428___0.454
H6_______262______207_______117_____0.2883___0.049 ___0.043___0.038___0.033___0.432___0.461___0.490
H11______266______211_______123_____0.2941___0.058 ___0.052___0.046___0.041___0.441___0.471___0.500
H3_______272______217_______127_____0.3027___0.064 ___0.058___0.052___0.046___0.454___0.485___0.515
H4_______276______221_______132_____0.3027___0.071 ___0.064___0.057___0.052___0.454___0.485___0.515
H10______284______232_______143_____0.3273___0.087 ___0.081___0.074___0.067___0.490___0.524___0.556


Stan

[77 TRASHCAN]

Ohhhh, all the mental anguish over a cam for a 7.6:1 350...LOL...post 2 has it covered. Sealed Power CS641 is a 066 cam

[242177P]

^^^ What he said. Especially as the 350 is only temporary.

Originally Posted by Stripes

I'm eventually going to swap it out. But in the interim ...

[ponyakr]

Originally Posted by 77 TRASHCAN

Ohhhh, all the mental anguish over a cam for a 7.6:1 350...LOL...post 2 has it covered. Sealed Power CS641 is a 066 cam

Just curious. You think that cam would be better in a low CR 350 than a small steep ramp Voodoo ?

Would it even be better than a Summit 2800 ?

To me, the 066 is a really small cam, even for a 350. Might produce a smoother idle, more vac, peak torque at a lower rpm, better gas mileage, & can get by with weaker valve springs.

But, in a 4-speed car, with 3.42 gears, what would be the advantage of an 066 ?

https://www.ebay.com/i/263203541022?...26pg%3D2385738

[77 TRASHCAN]

Don, In giving the selection enough thought, I'm not sure if the Summit, VooDoo, or 066 would make one horse difference between them.... The CS641 (o66) is likely the cheapest, that's what I'd use. I have one in a 1970 350, that's in my car right now. "70 vintage 350's are rated at 8.8:1, and they are likely less that 8:1, likely 7.6:1 just like the OP'er's engine. My car runs and drives OK...I believe it's as good as it can perform as it is...

and, I have a problem with something named VOODoo, and you know why...

[Steve C.]

"Unless you're a witch doctor, choosing the correct cam can be a nightmare. These Voodoo cams from Lunati are the answer! The gurus at Lunati have taken cam design to another dimension with profiles never before utilized. Only the world's best profiles are included in this line, making cam selection an easy choice. Voodoo incorporates 30 years of cam design experience with more recent developments in profiles, geometry, and tolerances, delivering some of the most aggressive ramp profiles ever used in cams."
Summit Racing




And many will disagree with the statement they have aggressive ramp profiles !

"You do not have to shut the valve faster to keep the charge from getting out. You have to design the cam so the charge, or inertia ram, is still filling the cylinder when you shut the valve.
Every cam I design, hydraulic, hydraulic roller, solid, solid roller, is designed using the same theory I have used for the past 29 years, and they all make excellent bottom-end torque for their duration."
UDHarold


.

[ta man]

My idea on cam selection..use a proven cam in a very similar engine/car combo to achieve what results you want.
Or take an experienced engine builder/tuners advise but hold that individual accountable if it runs like crap.

[ponyakr]

"...I have a problem with something named VOODoo, and you know why."



https://en.wikipedia.org/wiki/Louisiana_Voodoo

[Jay S]

Either build compression with the faster cam profile or narrow up the lsa and build compression from that. Best of both worlds would be doing both. Could probably have a fun ride with that H3 and H4 Ultradyne profile Stan has listed and have Bullet cams or Lunati narrow up the LSA to 108 and the ICL on 104. Build some compression, try to pack more power into the midrange and use the head flow that the low compression 350 can’t use for some cylinder scavenging. IMHO, that would be the best shot of seeing much hp gains over the 066. Might just be my preferences, but a 4 speed bird should have at least a little attitude in the idle. Not too many box cams out there that can do that without making HP worse. Not sure what you would gain hp wise, a set of headers and that cam swap and it would probably be noticeable over stock. JMHO. Certainly less boring.

[blueghoast]

I would just advance the cam that's in it with a 4* degree advance.

GT.

[ponyakr]

Well, there you have it. Just like most all the other cam threads, this one has LOTS of very different opinions.

Has ANYBODY EVER done any dyno or 1/4 mile testing of different cams in low CR 350 Pontiac engines ?

Seems like some say this one ran OK in my 350, or in my friends 350. But, I haven't read where anybody said we tried cam A, B, C, & D in the same engine, & this is the results from our tests.

If I win the Mega Millions tonight, I'll do it & posts the results, plus do a lot of other stuff nobody else is doing for the low budget Pontiac guys.

[pastry_chef]

Originally Posted by Stripes

would a cam change wake it up a little?

What does the exhaust system look like?

Originally Posted by ponyakr

I'll do it & posts the results.

If you were going to test a few cams with headers I'd donate a free custom cam to test. Something like max area from 2000 to 4500, winding down at 5000.