slade69

My 350 build is starting to realize. Pulled the engine out last night. This is an original engine of my car (or at least period correct). Solid main webs and #5 heads. I had a side tougts towars swapping to LS engine, but decided finally to stay with SBO.
Still, I have couple of questions for experienced engine builder on this forum:
1. Custom grind cams. Why are they always recommended, is there someting wrong in readily available cams? My plan is Comp xe262HR.
2. With this cam in mind, should I prefer Performer or RPM manifold?
3. Small journal SBC rods. Who the heck is selling them, 6.125 or 6.2 length.

joe_padavano

I moved your post to it's own thread rather than resurrecting a thread from 2014. Good luck with the build.

olds 307 and 403

Scat has the small journal SBC rods but they are only needed for a stroker build. Most cams are same for SBC, Ford etc. Cutlassefi is the guy to talk with when custom cams are mentioned.

captjim

Custom cams are NOT "always" recommended, there are plenty of cams that work fine. However, custom grinds are basically the same cost, so no disadvantage.

Intake and cam choice will depend on the final compression ratio, head work, and other factors.

slade69

Scat seems to list them. 6,125 long and 2" big end.
http://www.scatcrankshafts.com/rods/chevy-rods/


Yes I am searching the possibilities to make 3,5" stroke and 4,125"bore.

slade69

Yes true. 9,5-9,7 compression, slightly ported #5 heads, Stock valve sizes, Heat risers casted, middle exhaust center divider build. Comp XR262HR cam. Long tube 1 5/8 headers. Holley 600 vac. Cubes will be 374 or 355.
Cams advertised rpm range 1000-5000, so I might be better off with Performer than RPM.
Converter stall and gearing will be stock Cutlass 1969.

captjim

What pistons are you using?

cutlassefi

You won't make 400 with that combo, maybe not even 375 unless you have really good heads. Not enough carb and cam at the very least.

captjim

I must have missed something, I see no reference to 400 HP??

cutlassefi

My bad, guess I got him mixed up with another post, sorry.

slade69

It will be a summer daily , not aiming to that big hp. Altough, with these plans I believe to see 300+ crank hp.

slade69

Not decided yet. If I can find a crank grinder to offset grind my crank to 3.5 stroke, I'll be using 6.125 long small journak sbc rods and 1,425 compr height pistons, probably sbc400.

slade69

Any comments to intake with planned combo, Performer or Rpm?

captjim

Probably the RPM with that CR and cam, though it would like a bit more gear.

HWYSTR455

I originally ran the XE262 in a similar build, with a regular Performer, and it was a complete dog. Gave up at like 4500 RPM, was down on power across the whole RPM range, and the OE grind was a better performing profile.

IMO, it would be a waste of parts to build a stroker if you use that cam. A simple rebuild would be fine with that profile. Especially if you're doing just a cruiser.

SBOs like gear and stall for performance, and depending on the build, at least 3.42s and 2600-2800 stall.

.

1BOSS83

I'm running 9.5 with a RPM and headers and the combo is great. Although, as I look back my only regret is not having the heads ported and cut for the big valves as it would have made a major difference in my carb/intake/cam set up.

If I may ask (and let me please say first that I always look at things through a $/HP lens): Why stroke a daily driver? It's my understand that taking a non-DX to 4.125 can cause problems as the walls become very thin. In addition, speed pro 4.125 pistons have massive 18cc dishes and dated ring packs (these are for an olds 425 BB as I believe 400 SBCs are a larger bore). 3.5"S, 4.125B, 0 deck, .040 gasket, [assumed] 66 cc heads- you're in the 9.25 range, which is fine for a 218/224 cam (I used the comp 262xe for reference, I am not familiar with the model you listed).

Scat rods, custom pistons, custom crank work- $$$.

Just a hypothetical- stock rods, thin ring 4.087 pistons, w31 valves will be a wash $ wise and will perform very well with the RPM and comp 262. You'll lose 19 cubes from the original recipe, no debate but it is something to consider. I'd also urge caution in a 600 cfm carb, it'll have a hard time feeding a more free flowing 355 and that problem will compound as the cubes increase.

Good luck with your build.

cutlassefi

Adam, you're wrong on the piston info. I think you're talking about the L2323 Speed pro 455 piston? Not even close to what he needs.
He's correct in using the 400sbc piston along with a 6.125 sbc rod and a 3.500 stroke. Those Pistons are available in a variety of styles.
Use the RPM and as mentioned, ditch the idea of a 600cfm carb and go with a 750 instead.

Jmo

captjim

4.125" is only .068 over, that is no problem at all for 99% of the gas solid web 350 blocks out there, IMHO.

slade69

[QUOTE=HWYSTR455;883864]I originally ran the XE262 in a similar build, with a regular Performer, and it was a complete dog. Gave up at like 4500 RPM, was down on power across the whole RPM range, and the OE grind was a better performing profile.

Must have been something wrong if ran better with original cam?!?

slade69

Here are some of my toughts. Crank needs to be grinded anyway, so why not offset gring to gain some stroke?
I think stock Olds rods are quite lousy. Big ends tend to get out of round easily. I have measured them from 2 engines and both were out of tolerance. There are some others thinking same way (Trovato, for example). So I want new rods anyway. SBC rods are the key, and it's only natural to use SBC pistons, they fit to rods without any tinkering. Also, they are available and affordable.
Cubes are never wrong. Even in a weekend driver some extra torq over the band is ok with me.
Why 4.125 bore? I have an extra 68-72 350 block that has been sitting a long time with some water in bores. My machining guy has measured the block, and I can rescue it to use with 4.125 bore. There should be no problems with that size. Newer windowed light casted blocks are different story.
Why 600 carb? Simply because I have it. There is a guy in this forum with copper colored cutlass running high 12:s with 600 carb. He even tried bigger and did not gain much. Also, the carb is on top of the engine, easy to go later 750, if pulling lots of wot vacuum.
Cam is this one
http://www.compcams.com/Company/CC/c...csid=1182&sb=2

slade69

You are probably right but I can not afford everything this winter. Next winter TH 350 will be swapped to TH2004R with a bit higher gears.

captjim

I have said many times that the added cost of the stroker is more than offset by the added benefits; better parts, more cubes, longer stroke. I also think the carb is too small.

cutlassefi

If you're sticking with that Comp cam and 600 carb then there's no reason to go with an RPM intake. It'll fall on it's face at anything over 4500 anyway. The RPM intake alone won't fix that.
And again if you're staying with that combo I wouldn't do the stroker setup either, it'll just be that much more anemic. Just grind the crank to the large journal SBC size and use a 6.200 rod with the same 400sbc piston.

Thanks.

slade69

Ok, let's say I'll dump the idea of 600 carb and go 750 and RPM. Any good suggestions for cam instead of XE262HR. I would like it to pull strong to 5000rpm. Falling on it's face over 4500 is not my goal.

cutlassefi

Yes a custom Lunati grind I've done for a few stroker builds. 221/227@.050 with .542 lift I believe. It'll pull thru the low 5000's.

HWYSTR455

Would you happen to know the advertised on that grind? Be curious to know.

The Comp XE 262 I ran was the HFT version, not the HR, and was slightly larger than the HR version (218/224 vs 210/216 on the HR):

http://www.compcams.com/Company/CC/c...csid=1170&sb=2

HRs in general spec out a little different, but suspect they perform roughly then same.

I went to this cam after that fail, and it was day/night (220/227):

http://www.crower.com/camshafts/olds...m-280-hdp.html

That Crower grind pulled to like 5400 or so with my combo (performer/650cfm), and I stepped up to an RPM and 750 at that time. Like I said, day/night. With the RPM and 750, it pulled to like 6000.

It dropped like almost 1 sec in the quarter with that change alone. (cam, intake, carb)

And no, there was nothing wrong, except for the cam IMO.

.

slade69

Are those custom grinds availabe as hydraulic roller?


Does Lunati have hydraulic roller lifters for s 350?


Would this kind of cam be usable with stock converter/gears?




Is there som magig in stroker camspecs? Or is it just that bigger cubes likes a bit more duration?


Huh, a lot of questions...

coppercutlass

If you are talking about my copper colored cutlass. I never ran 12's with the 600 carb just for what its worth. I did run 13.3's @ 103 with the 1405 eddy. currently my junk runs 12.6's @ 105 with a 750 holley 3310. Technically i could have ran 12's with a 600 cfm carb BUT ! my converter was a big factor holding me back at that time. 103 is enough mph to run 12's but my 2.02 60 ft. at the time was horrible.

slade69

In my book 13,3s with 600 carb is pretty darn fast! If I recon right you have 355cid and with that time you have to be somewhere 350ish hp with 600 carb.
12,6s and you have to be somewhere 400hp I assume.

coppercutlass

My current combo based off track numbers is appx making 370 ish. I wanted 380 but I left plenty on the table for improvement. That particular combo I'm running now is pretty basic. Nothing that really jumps out as exotic or expensive.

slade69

Damn. Got just bad news from machineshop. They have pressure tested my #5 heads and there is a leak from water jacket to combustion chamber.
Does anybody have a decent sbo heads to sell?

cutlassefi

No problem.

slade69

I had my #8 heads also tested and one of those leaks also. They both are cracked from valve seat to water. This must be quite common with these old Olds heads?


Now I am trying to find a set of SBO heads. Minimum I need is rebuildable non-cracked cores. No luck so far. Only located one set of 5A heads (80's 307). They are ported/milled. Not sure yet if valves changed to bigger ones. These might be usable in 350, any opinions?

olds 307 and 403

Actually no, they are usually good for cracks other than the 3A heads. Unless you can find a set local or cheap, Procomps might be a better choice. 5A heads would need a lot of port work and bigger valves, it would limit flow even with maximum porting.

slade69

Who is selling these procomps? How are they different compared to Edelbrocks?

HWYSTR455

Bernard Mondello Racing is the best place to purchase these from what I understand. They prep the heads and assemble them, and there are a number of options, so may be best to call.

As for differences compared to e-heads, search, there's plenty info out there on them. One difference I believe is the Edelbrocks have better chambers, but it will matter when it comes to what you're trying to do.

ProComps released a new improved head, they have shipped, and vendors are waiting for them now. Considering the cost savings, I will be in line for a set.

.

olds 307 and 403

It will interesting to see if they can be ran as is. If I can get a complete for $1000 a pair and don't need work other than milling, count me in. I wish they would offer them in the current 83 cc and a 70 cc chamber out of box.

HWYSTR455

Bernard has the new castings in, and is advertising them for $1375 assembled & shipped. Milling for a SBO is extra, but not too bad from Bernard.

http://www.ebay.com/itm/BERNARD-MOND...YQG9SQ&vxp=mtr


For those prices, doesn't really matter what CC chambers are offered out of box, there isn't one out of box head I can think of that doesn't need to be gone over. If you get them boxed for $1000, you will probably spend $600+ to get them prepped, plus some to mill too I bet.

Those heads are a steal, and half or less the price of any other offering.

.

67 Cutlass Freak

I have an ample supply of cores that I can build to your specific needs. I have ported SB heads that flow way better than the Pro Comps out of the box & real close to stock Edelbrocks. Shoot me a PM.

slade69

PM sent.