[Erikmurray]

Hi hope you’re all doing well. I am buying a 78 WA short block with 048 ram air 3 heads this weekend. I plan on tearing it down and getting it cleaned up maybe even bored .030 over. I would like to put a ram air 4 camshaft into it also, and I was wondering if anyone else has done this or if anybody has suggestions, or if I should just use the 744 ram air 3 cam. I will gladly listen to top end and bottom end suggestions as this is my first ever build.

Thank you

[pastry_chef]

Originally Posted by Erikmurray

should just use the 744 ram air 3 cam.

Depends on factors such as:

what compression ratio you will be targeting,
transmission type and converter stall speed if auto,
rear axle ratio.
Will you be using the existing valve springs or installing new.
what rocker arms and ratio.

[tom s]

You really need to post all the specs of the engine,trans,and rear gears etc.A true RA IV cam was only avail with deep gear like a 3.90 and 4.10 so it can be a bad choice for many street combos.Tom

[Erikmurray]

Originally Posted by tom s

You really need to post all the specs of the engine,trans,and rear gears etc.A true RA IV cam was only avail with deep gear like a 3.90 and 4.10 so it can be a bad choice for many street combos.Tom

Well whatever car I end up getting to put it in, if doesn’t have the right gears I plan on putting 3.90s in. I don’t know what trans it’ll be yet because I don’t have the car. But it more than likely be a th400 or th350. I was told the motor has like 10.5:1 compression so I’m going to change the pistons to get around 9.5:1 so I can run it on pump gas safely.

[Erikmurray]

Originally Posted by pastry_chef

Depends on factors such as:

what compression ratio you will be targeting,
transmission type and converter stall speed if auto,
rear axle ratio.
Will you be using the existing valve springs or installing new.
what rocker arms and ratio.

I’m shooting for something around 9.5:1 so I’ll be changing pistons. I found comp valve springs that Butler Performance recommends for the ram air 4 cam so I will probably use them. I haven’t decided if I’m going to keep the stock rockers or change to a better aftermarket like Scorpion with a 1.65 ratio. I’m not sure how reliable the stock rockers are.

[ponyakr]

Not many will recommend either of those cams for a pump gas 400.

Especially with the 041, you just lose too much low end power.

There are much better cams for a street 400.

I've said, many times, that it does not make any sense to use a cam that will make lots of power over 5000 rpm, if your street car will spend MOST of it's time from idle to 4000 rpm.

For stop-&-go driving, low rpm torque is what you need.

BUT, if all you want is a lumpy idle & a cam that will pull to 6000 rpm, those cams are available.

I'm guessing that a cam with an intake lobe duration somewhere in the 220° @ .050 range would be a good compromise. 230° for 5000 + rpm power, and closer to 210°, for a smoother idle, more vac, & more torque from idle to 3000 rpm.

There are quite a few choices, with numbers in this range. Lots of guys recommend an 068 clone, such as the Melling SPC-7. The Summit 2801 is a higher lift version.

Here's a 213° Howards.

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

The Lunati 10510312 is near the middle.

https://www.lunatipower.com/street-m...8-276-286.html

Here's a 226° Crane.

https://www.summitracing.com/parts/c...IaAusEEALw_wcB

The 041 clones & similar versions of it are near the 230° number.

Here are a couple with less adv duration, which should provide a little more low end power, than the 041 clones.

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

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

Some guys like a Lunati Voodoo, for most any high performance 400. Most say these cams require more spring pressure than cams with more conventional lobe shapes.

https://www.lunatipower.com/voodoo-h...8-262-268.html

Unless you wanna build for max power, I think the 1.65 rockers just put extra strain on the valve train, which is not needed.

BUT, lots of guys here recommend high lift roller cams, 1.65 rockers, & high spring pressure, so you won't "leave anything on the table". Just depends on who you ask.

[ponyakr]

Just looked up that WA block. There was no WA, in '78. So, unfortunately, it's probably a '77 WA block. That's not good, because it's a casting number 500557 block. MOST say those blocks should not be used for high performance builds.

There have been many "557" block failures. Those blocks have thin main webs, which are known to crack at a main cap dowel pin hole.

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

PS: Many will say the blocks are just fine for up to 400hp. Some will say they raced 'em for years, without any problems at all. Just wanted to let you know, BEFORE you spend a lot of money building an engine, using that block. I'd go with a 481988 block, which was used from '71 thru early '75.

[Erikmurray]

Originally Posted by ponyakr

Not many will recommend either of those cams for a pump gas 400.

Especially with the 041, you just lose too much low end power.

There are much better cams for a street 400.

I've said, many times, that it does not make any sense to use a cam that will make lots of power over 5000 rpm, if your street car will spend MOST of it's time from idle to 4000 rpm.

For stop-&-go driving, low rpm torque is what you need.

BUT, if all you want is a lumpy idle & a cam that will pull to 6000 rpm, those cams are available.

I'm guessing that a cam with an intake lobe duration somewhere in the 220° @ .050 range would be a good compromise. 230° for 5000 + rpm power, and closer to 210°, for a smoother idle, more vac, & more torque from idle to 3000 rpm.

There are quite a few choices, with numbers in this range. Lots of guys recommend an 068 clone, such as the Melling SPC-7. The Summit 2801 is a higher lift version.

Here's a 213° Howards.

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

The Lunati 10510312 is near the middle.

https://www.lunatipower.com/street-m...8-276-286.html

Here's a 226° Crane.

https://www.summitracing.com/parts/c...IaAusEEALw_wcB

The 041 clones & similar versions of it are near the 230° number.

Here are a couple with less adv duration, which should provide a little more low end power, than the 041 clones.

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

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

Some guys like a Lunati Voodoo, for most any high performance 400. Most say these cams require more spring pressure than cams with more conventional lobe shapes.

https://www.lunatipower.com/voodoo-h...8-262-268.html

Unless you wanna build for max power, I think the 1.65 rockers just put extra strain on the valve train, which is not needed.

BUT, lots of guys here recommend high lift roller cams, 1.65 rockers, & high spring pressure, so you won't "leave anything on the table". Just depends on who you ask.

As long as I put pistons in with some amount of dish to drop the compression to something around 9.5:1 I should be able to run pump gas with these cams. Yeah I may lose a little bit of power but probably not enough to notice. Thanks for the input this is definitely a subject that will always have differing opinions. I torn between 1.5 and 1.65 rockers, and I’ll probably go with 1.5 for the same reasons. I figure if they sold that cam in a street car back in 1970 than it must have been streetable. Like I said I haven’t decided yet I am still weighing my options. I really appreciate the feedback and the links to possible substitutes.

[Will]

In 1970 100 octane leaded gas was available and running 10.5:1 or higher compression was no big deal. That makes a big difference with a cam like the 041.

If you're willing to spend the money on valve springs, gears, and a converter then there's no reason to run a factory cam. Cam design has come a long way in 50 years and hobbyists aren't faced with the same constraints the factory engineers were.

[steve25]

A good running 400 using the RA4 Cam with its big overlap numbers is highly dependent on a 10.5 compression ratio and performance wise having a 4 speed with atleast 3.55 rear gears in the car!
And this is a 10.5 compression with iron heads, not Aluminum heads that need one full point higher ratio just to be on par with a iron head in a A verses B situation!

Back in 1969 and 70 the factory would not make you a A or F body car with the RA4 motor without having 3.90 gears in the rear or steeper!

[jamaca85]

sell the heads and grab a pair of aluminum 72cc heads, the car will do good with 91 octane gas, more power too.

[Erikmurray]

Originally Posted by jamaca85

sell the heads and grab a pair of aluminum 72cc heads, the car will do good with 91 octane gas, more power too.

That is a route that I am contemplating, do you know how much 048 heads normally sell for by any chance?

[steve25]

It's not the iron heads that are the problem if your rebuilding a motor that needs new Pistons in relation to compression ratio, it's the Cam pick!

In fact if your going to error on the side of having bit too big of a Cam, then your far better off with the smaller port volume of a iron head then a aftermarket head!

[Erikmurray]

Originally Posted by steve25

It's not the iron heads that are the problem if your rebuilding a motor that needs new Pistons in relation to compression ratio, it's the Cam pick!

In fact if your going to error on the side of having bit too big of a Cam, then your far better off with the smaller port volume of a iron head then a aftermarket head!

Yes, I just did a little research and came to the same conclusion, and I’d rather build a stock Pontiac motor with the iron heads it’s seems cooler to me.

[Erikmurray]

Originally Posted by ponyakr

Just looked up that WA block. There was no WA, in '78. So, unfortunately, it's probably a '77 WA block. That's not good, because it's a casting number 500557 block. MOST say those blocks should not be used for high performance builds.

There have been many "557" block failures. Those blocks have thin main webs, which are known to crack at a main cap dowel pin hole.

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

PS: Many will say the blocks are just fine for up to 400hp. Some will say they raced 'em for years, without any problems at all. Just wanted to let you know, BEFORE you spend a lot of money building an engine, using that block. I'd go with a 481988 block, which was used from '71 thru early '75.

Thanks for the heads up.

[Jay S]

Originally Posted by Erikmurray

Thanks for the heads up.

We used a ra4 cam (melling spc-8) in a Ram air 3 70 judge, 4 speed w/3.90s. Better cams to use imo that a 744 in a 400. Summits 2802 is a good high lift substitute for the 744. If you end up with compression over 10 scr imho a ra 4 cam with Rhoads lifters works better than a lot of the newer modern replacement cams. Crower’s 60919 and the 60243 are both higher compression cams to.

We have been using a lot of Bullet/utradyne’s. The last 400 I helped with that had small chamber mildly ported heads used a Ultradyne 283/291 235/243 @ .050, 110lsa, .550/.550 lift with 1.65s HS rockers with Rhoads v series lifters.


FWIW. If you do have one of the week blocks. I have a couple main cap girdles designed to push the hp on them. Both use a stock oil pan, images are below. Production is little over a month away, version on the bottom image is pretty reasonably priced. It is not a current pic though, I need to take another photo of it in it’s latest form.

One of my current engine projects is a 77 400 WA 4.21” well over 500 hp. I am working on plans for a higher HP weak block build to see what kind of abuse it will take.

[OCMDGTO]

Cliff Ruggles had a great thread on a 400 build he did, you should search for it. He used iron heads and a Crower hyd flat tappet cam. Very smart and cost effective build. I would get a different block, too. I personally ran a 400 w 16 Heads and a Comp XR288 HR(little bigger than a RA4) for years with 3.23s & 3.50s and it was a very streetable combo. Good luck

[STEELCITYFIREBIRD]

Originally Posted by Erikmurray

That is a route that I am contemplating, do you know how much 048 heads normally sell for by any chance?

Condition, date code make a difference. Be aware that chamber volume can vary from ~66~72 stock, depending on what they came off and when it was produced.
The only way to know for sure is to CC them.
I have an early set that are 64~66 cc, I can't recall exact # off hand. Early castings and have been surfaced. Pristine with full phosbronze guides. Stellite exhaust seats, new valves,68404 springs, nice valve job and some bowl and minor chamber work. If I got 1200 for them I'd be very lucky, unless I found a niche buyer that needed a certain date code then I could command much more $$$$, they do match on date codes.
It cost that much 1200... or more to get them in this state now, without the cost of the castings!

All depends on current condition , buyer and market you bring them to.

CAsting # is 048 on center exhaust or 48??

[Erikmurray]

Originally Posted by STEELCITYFIREBIRD

Condition, date code make a difference. Be aware that chamber volume can vary from ~66~72 stock, depending on what they came off and when it was produced.
The only way to know for sure is to CC them.
I have an early set that are 64~66 cc, I can't recall exact # off hand. Early castings and have been surfaced. Pristine with full phosbronze guides. Stellite exhaust seats, new valves,68404 springs, nice valve job and some bowl and minor chamber work. If I got 1200 for them I'd be very lucky, unless I found a niche buyer that needed a certain date code then I could command much more $$$$, they do match on date codes.
It cost that much 1200... or more to get them in this state now, without the cost of the castings!

All depends on current condition , buyer and market you bring them to.

CAsting # is 048 on center exhaust or 48??

All I know is that they are 048 heads from 1969. I haven’t picked the motor up yet to look deeper into it. The guy told me the combustion chamber is 72cc which lines up with I found for a 1969 ra3 head.

[Erikmurray]

Originally Posted by STEELCITYFIREBIRD

Condition, date code make a difference. Be aware that chamber volume can vary from ~66~72 stock, depending on what they came off and when it was produced.
The only way to know for sure is to CC them.
I have an early set that are 64~66 cc, I can't recall exact # off hand. Early castings and have been surfaced. Pristine with full phosbronze guides. Stellite exhaust seats, new valves,68404 springs, nice valve job and some bowl and minor chamber work. If I got 1200 for them I'd be very lucky, unless I found a niche buyer that needed a certain date code then I could command much more $$$$, they do match on date codes.
It cost that much 1200... or more to get them in this state now, without the cost of the castings!

All depends on current condition , buyer and market you bring them to.

CAsting # is 048 on center exhaust or 48??

And based on the pictures and what he told me the heads really just need a little clean up.