Sure, you can deck to drop chamber volume, but why bother? Take a little time and look around. As stated above, finding a set of big valve heads with the right chamber volume shouldn't be too difficult, they're out there. I would much rather spend my hard earned ducats buying and freshening up a set of already in the ballpark heads, than blowing money on decking the heads AND intake manifold, spending more on fitting bigger valves, then spending yet again more money on freshening them up! You could always cut to the chase, break open the piggy and spring for aluminum E-brocks or KREs
On my altered I only took .010 off and ran low compression and did just fine, I have now switched to #13 for the compression and since a drag car only. Jon
I was just given a '71 350...complete...so while those aren't perfect heads, those are what I'll run for now...thanks for all the advice guys, keep it coming...
Ahh...very good question, gr***hopper... To get your 400 to 9.3 :1 you would need exactly 80cc chambers. 9.3 is great, but where are you going to find 80cc chambers? There are only a few casting #s that are 80ccs, and two of them have the small valves. So, I suggest a 6X-4 head (94ccs) that will get you about 8.5 not because they are a perfect match, but because they are one of teh most common heads you will find. 6Xs are plentyfull (and have big valves) and you can shave off a few thou and get them right at 9:1. It's kind of a trade off...cheap, easy to find heads will only get you 8.5 or 9, but expensive heads (670s 72cc) will get you 10.5 which is WAAAAY too much. I always lean to teh conservative side on Pontiac compression, particularly with a heavy car, tight converter and street cam. My 64 Ford had a set of 670s on a 400 and I ****ing hated em. Swapped for a set of 6Xs and never hear a ping. The fact that I can now run my timing where it needs to be greatly outweigh teh slight loss in compression. The point or half point you might gain by searching for the exact set of heads you need really might not be worth the pain in teh *** factor, when a pair of 6Xs are right in front of you. And, on the subject of camshafts....hyd rollers are the best for performance, but not so good on the pocketbook. My Pontiac makes over 600 horse on a regular old hyd cam right out of teh Crane catalog. Gimme a holler if you need anything. -Abone.
One more thing.... There is a dude on ebay selling these valve covers for 119 buy it now. I am tickled ****less with them. When was teh last time you saw a set of Pontiac valve covers for 119 bucks?? -Abone.
So then the 8:1 350 heads I'm picking up this weekend won't be too bad...I'm super stoked with all the advice from you guys...and stop suggesting Ram Air cams, I won't run one with this setup...
Ruiner, a couple or three others have mentioned the obvious choice for your present combo. It is the 068 camshaft. Made by Melling and available practically everywhere; Autozone, Advance, any independant parts store. With that rear ratio and an automatic, that is your best overall choice. Now of course if you decide to change heads, ******, rear ratio, etc; then there are others that are better.
All stock 400's running an 068 cam also have over 10.5:1 compression...the most I'll have right now is 8:1
Skip the 17s . They are pressed in studs and small valves. With your combination, the 2801 Summit cam should fit the bill, 114 degs lobe separation will give a very broad torque band If you had the higher compression heads like 670s,16s,62,48s,12s 13s. Then you could go with a bit more duration. I have 3 1968 Firebirds and all have the higher compression heads and run strong. The car I race has a cam like the Summit 2802 and it kicks *** . At a weight of 3810 lbs it does 0-60 in 3.8 seconds , 0-60ft in 1.67 seconds and a 12.5 inthe quarter at 107 with non ported #16 heads. It also never gets past 175 degs in hot summer traffic. I would say, you have one of the worst intakes for a Pontiac, too small of a carb for a Pontiac 400. Im running an 800 Holley DP and on the dyno with the wide band, it ran about 13.2 parts to 1 on the scale. I had a 69 with a 400 and 6X heads and it would fry tires, 4 sp with 3:55s. Unfortunately the top end lacked in the 1/4.
Been doing some digging on the wallace racing website, a 400 with 8:1 comp and a 067 cam made 300hp stock, so maybe the 068 cam isn't too bad...now, I need to learn how to use my Sun 504 distributor tester and learn to recurve my distributor...
The ram air iv would **** with a 400 and 6 x heads, way too low of compression. For under $100 get the Summit 2801 with lifters. Been into Pontiacs for 27 years in a very big way. The RA iV is totally different in a 455. In a low compression engine, you would have to rev the piss out of it to feel any power. Oh and a hydraulic roller for a Pontiac will be around $800 for cam and lifters.
What's wrong with an older dual plane Weiand intake? The 600cfm carb I have is only on there because it's the only 4bbl I have left...I'll try and find a 750DP this spring/summer...
I had a ram air IV cam in a high compression 400 in my 67 GTO. That thing would really rev. It ****ed below 3000 rpm. Combine that with 3.55 gears and you have a car that takes off like a slug on salt. My 4.3 liter S-10 actually had more get up and go than my GTO with this cam. Ram Air IV was a package. I works best with the correct intake, heads, rocker arms, exhaust and 4.33 gears. I would avoid it if possible. Rhodes Lifters are kind of a band aid fix for these cams in the wrong application. There are better cams out there for your combo such as the 068 or the Summit cam. Dave
I can't decide between going to Napa and ordering the Melling 068 or calling Summit and getting the 2801...I think the convenience of Napa might win...
If you have 8:1 now, you will still have 8:1 with the 068 cam. In a Pontiac, the heads determine the CR, not the camshaft. The summit 2801 is a clone to the 068. Others have had good luck with it. I just prefer the Melling 068, as it is the 'factory' piece. I've used 6 or 8 in different combos from a 326 to a 421 and were satisfied with all of them.
But the cam can bleed off compression at different rpms. Thats how I get away with 10-1 on pump gas and some people with the same engine and heads but different cam detonate bigtime.
The old Weiand is a very restrictive intake. Never did work good. Even the factory cast manifold from 1967-1972 flowed better. The Performer intake flows the same as the factory manifold.
While it is true that Pontiac heads determine static compression, a cam with lots of overlap will bleed off dynamic compression. The 744 cam has more overlap than most of the other Pontiac factory cams and that has to be taken into account when putting a combination together. My super secret cylinder head preference is the 061 head from 1967 full-sized cars. Yes, they have pressed-in studs, but they have big valves, open chambers and will yield a compression ratio in the 9.2 range with a standard bore 400 engine. Nobody is looking for these heads since they don't have the same reputation as the 670 head so they can be had for cheap. I bought a pair of them from a Pick Your Part in Sunland, CA for $50. I put new springs on them, cleaned them up and put them on. For less than $100 I had a big boost in power and when I got around to swapping the cam it was good nigth nurse! That's my two cents.
For what ever its worth, You could put a little more CFM on that engine, and a little more gearing wouldn't hurt that 400 either. A Melling SPC-8 would be a great street / strip cam for your application. Its a Ram Air IV cam. Axle
BTW, The SPC-8 that i am recommending is a Hydraulic Cam that will give you absolute no trouble. Set it up once and you're done! I have used this street cam for over 20 years and various applications. If this is a bit too much step it down a notch and Melling makes the Ram Air III Cam which will work very well. best of luck
So what intake that's easily available should I be looking for? Is there any way to get my Weiand manifold to perform better? I'm heading to NAPA today to put in my order for an 068 and gaskets, tomorrow I pick up my heads...good times
I personally have'nt run any Weiand 4 barrel intakes but you arent building an all out ****d Ape machine so it should work out ok for ya. But, an intake i have had great results with is a Holley Street dominator.
As mentioned the 67-72 cast iron intakes works very well on the street for the smaller engines like a 400. Than you could get a 750 cfm q-jet. I never had too good luck with Holleys myself, my q-jet works very well. Thats what i'm running on my 400/670 headed engine (10:1). I found a Buick 800 cfm and had it rebuilt to my engine specs. Btw i'm running a Comp Magnum 280. 2700 stall and 3:90 gears. The smaller chamber 6x-4 heads would be the best If you find a set, there on 350's. The secondary stamping is on the ac mounting boss on the side of the head. With your o68 setup, you will be able to retain your stock pushrods and rocker arm set up. You start going bigger than you'll need to replace your rocker arms and studs and go to an adjustable valvetrain.
Just if your wondering about the looks factory cast iron intake if you go that route, here's a pic of mine, I ground off the bosses I wasn't going to use and all the casting numbers. I also cut the water crossover off so I could align the ports after I gasket matched the intake.
Who wants to order a Melling 068 cam for me so I can finally use up the money in my Paypal account? My Napa guy said he can't get one...
Ruiner, Summit is selling their version of the 068 in their Ebay store right now under their part number 2801 for $60 and they take Paypal. The auction number is 220205833349.
Thanks for the link, but S***mit strikes again with their shipping and handling...that $60 cam turns into $82.75 after their shipping and handling charges, and then I still have to buy lifters...I'm gonna keep searching ebay and see if any other cams come up...
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