Bluemeanie

Apologies if this has been beaten to death. I tried to do my research, but couldn't find an answer to this specific question.
I have a 1970 SX, 455, L31, (4 barrel) E heads, bone stock minus the HEI. I also have an original W-25 hood on the car, which I won't modify.
This motor runs perfect, but has 100k on it, so I'm not going to go crazy with mods until it needs to come out. With that said, I'm lucky if I put 500 miles a year on the car, so that may be a while. I just rebuilt a poncho 3:55 posi rear for the car out of a GTO (replacing the 2:73) to help with waking it up a bit, and was wondering if simply changing the Intake manifold, and setting up the carb for it would make enough of a difference to be worth it. I'm looking for power, not asthetics. I know there are only a handful of Intakes that will work with the Hood, so without going with something like a performer etc...
Would an old Edelbrock OB4, or a repop w-30 intake be worth the trouble and $??
Thanks for your thoughts!

70Post

My bet is you will gain little, if anything, with that swap.

As far as swapping for a repro or original alum W30 intake....you definitely won't gain anything, HP wise, as they are a duplicate of the cast iron 4 bbl intakes (other than the exterior lettering, PN's, etc).

Also....any "perceived" gain might be from supertuning/tweaking/rebuilding the carb itself which may or may not be currently performing optimally and/or may respond to some of the typical changes like secondary metering rod changes, secondary air valve wrap changes, etc.

I'm no engine builder but my thinking is that the cylinder heads, with the stock ports, may be the "pinch point" so a change to a freer flowing intake may be an exercise in futility if that's the case.

Of course, if you were planning on rebuiding the motor down the road and know now that you'll likely be adding some other HP improvers such as a larger cam, larger exhaust, bigger valves, some mild head porting, etc....well, now you have a good excuse to get an intake and use it now (it's not like it's going to wear out!).

Weight savings is the same as gaining HP but in this case you wouldn't save enough weight to get a "seat of the pants" feel in accelaration improvement IMO.

There's always the "placebo effect"!

matt69olds

I would think installing a camshaft would be a much better way to go. Camshaft technology has come along way in 40 years. That would also give you an excuse to replace the nylon covered timing chain and ensure the engine will last awhile before NEEDING to come out.

joe_padavano

The thing is, you need to be sure all the mods match and the engine works as a system. Just swapping the intake won't make much change (despite what the butt dyno might say). Just swapping the cam won't make much either. Swapping BOTH the cam and intake, rejetting the carb, and lowering exhaust restriction will make a LARGE improvement, however.

Kennybill

Is the rear-end installed yet? That alone should really "wake" it up. I would drive it 500 miles before the next modification. If you want more, then chain/cam/intake&carb/better exhaust. Your on the edge of a slippery slope call MAW. Might As Well. We've all been there. Ken

Bluemeanie

Thanks guys,
I think deep down I knew what Padavano said, but I don't know these Olds motors like some of these guys. Since the carb is coming off anyway, I just thought I'd check. And yes, I agree, I'm on the verge of a MAW catastrophe,..so I must tread lightly!!
The rear is not in yet,..I'm waiting on my new gas tank to show up, and will do it all at once.
Since we're here,..let's say "for argument sake" I decide to go with a new cam, manifold, change the timing gears and chain, and set up the carb for it...
Opinions on that set up? Is there a good basic "mild" combination that has been proven? And again, I'm limited on manifold options, and won't fool around with headers. Trying to squeeze everything I can out of it, with a budget, keep it reliable, and keep it a nice cruiser. I can certainly live with it the way it is, but it's hard to not want a little more!
Thanks again!

Dan K

BM - Just thought I'd chime in here as I am interested in responses to the question(s) you raised as well. Hope I'm not hijacking your thread.

And also, since I have a "1970 SX conv dolled up as a 442 (by PO)"... in Seattle - and Viking Blue(?) as well? WTH? What are the chances of that?

I however have very recently started some recent "bad" internal engine noises on my #'s match L-33, so am doing my research for a rebuilt. Like right now - before the sun comes out (in July!).

As it sounds like you do, I want to keep it mostly stock - don't really want headers after reading about everyone's headaches, but have been thinking an upgrading the cam and maybe a performer intake (or repop w-30 - even if the intake is more for looks and a nominal weight reduction).

So how 'bout it guys? You've got two guys with stock 1970 455 E-blocks that want to do an incremental step up in performance, without going too crazy. What are some suggested groupings of upgrades, in keeping with Joe's comment of all things working as a system?

My setup: '70 455 L-33 stock as well, except orig 2bbl swapped for Q-jet (702057) & Olds iron intake, Pertronix Egnition, TH400, 3:23 Posi Olds rear. Dual exh with crossover, on stock W&Z manifolds.

Bluemeanie

Dan,
That's why I started this thread,..you can buy an Edelbrock kit for all kinds of Motors,..they may not be perfect, but they work. I put a performer kit (Cam/Manifold/Carb)on my Cuda 340, and it ran right the first time I started it. We have to look to others who have tried and failed, and I can't find any real consistant information anywhere. Soooo... welcome!
And since your in Seattle as well...better get on it to get that thing done before the sun goes back into hibernation. Our season is SHORT! Hope to see you cruisin around this summer...
I know somebody out there has done this and had success,...so ya,..c'mon....
give it up!!!
Thanks...!
Brian

rustyroger

Changing the timing gears & chain is probably a good idea with your mileage, but unless you sort out the exhaust you wont see much benefit from other mods, everything (exhaust, inlet, carb, heads etc) is dependent on everything else. I'm not saying you wont see a little more hp but you won't get the best from your engine unless you do the whole package.

Roger.

redoldsman

In a one word answer to your question, NO. That is just my opinion and like most everything else I have, is probably worth absolutely nothing.

Run to Rund

Choosing a good camshaft is one facet to that mod; then there is installation, and using good oil so you don't wipe lobes on break-in, etc. Yet if you have to list the possible mods--headers, cam, intake, carb jetting, I would start with metering rods for the carb, then camshaft, then headers (or headers and cam picked together), with the intake being last. NHRA stockers run 10 second quarter mile e.t.'s with the stock intake.

matt69olds

Since you don't want the hassles of headers, that limits you a little on camshaft. I would think a MILD camshaft upgrade, new timing chain, a better exhaust (doesn't have to be LOUD, just better flowing) and a little carb work will really make a huge improvement. Maybe CUTLASSEFI will comment, he has probably forgotten more about camshaft stuff than most of us know.

oldcutlass

I would go for gears, best bang for your buck.

Bluemeanie

I'm already doin the gears,..
The Cam/timing chain/carb tune thing sounds great...
I would Love to hear from CutlassEFI,.....or someone who has done/knows such a mild change...
I don't really want to, or have time to experiment. Looking for a proven setup...
Anyone???