i have heard that there are a few parts on the buick 430 engine that can be used on the 455. i have seen articles on 430 exhaust manifolds that say that they are better flowing and less restrictve (due to their shape) than the 70-76 455 exhaust manifolds. also i have heard that '67 430 heads are also good. why is this (if it is true)? i have found a '68-'69 riviera with the engine inside the car (i was coming home last night and saw it in the parking lot of a body shop). the car is striped, but still has the engine and body parts. i want to swing by tomorrow nad ask them about it. anyway... just wondering if there are any good parts on the 430 that can be used on a 455 to give it a stock look, but great performance. john
Here's some information I found a while back on Buick heads: "Big Port" heads are as follows: 1967 casting numbers: 1372963 (430) 1382983 (430) 1382985 (430) 1382986 (430) 1968 casting numbers: 1384720 (400) 1382983 (430) 1382985 (430) 1384720 (430) These flow about 5% better than regular heads. What Heads Flow the Best? Through the years, Buick made numerous sets of heads for the 400, 430 and 455 engines. These heads are largely interchangably. Generally, the rule is that early heads can be used on later blocks but later heads will not fit early blocks. I can't say that this is true, however, later heads (certainly 72 and after) came with larger chambers (for reduced compression engines) and various smog and emissions modifications. So, from a performance standpoint, most people will want to use 71 and earlier heads. The question is what heads flow the best. The following is a list of the stock factory non-stage heads that flowed the best. NOTE: If using earlier heads on a later block (67-69 heads on a 71 or later 455 Block), you need to block the upper front oil passage hole (located beside the upper front head bolt hole) on the drivers side of the block. If left unplugged, serious oil leakage will result when 455 rocker shafts are used. 1. 67-68 400-430 "Big Port" Heads (These heads flow about 5% better due to larger intake ports). 2. 70-71 455 Heads 3. 69 430 Heads 4. 72-74 455 Heads 5. 75-76 455 Heads The information listed above does not include porting. Ported heads will obviously flow better than any non-ported heads. Good port jobs, however, are EXPENSIVE. The list is intended to identify the best flowing heads for people who don't have the bucks to port their heads. My suggestion is to take a set of the 67-68 Big Port 430 heads and cut them for stage 1 valves, back cut the valves, match the intake manifold ports to the intake ports of the head. If funds permit, then go a little further and unshroud the area around the new big valves in the combustion chamber, and polish the combustion chambers. Big Block Performance Heads Tips Block Exhaust Crossover Install cap plugs (2 per head) to block off the crossover passages. If you remove your cylinder heads, the better course of action is to have a quality head shop fill these passages flush to the exhaust port. This keeps hot exhaust gases out of the intake manifold giving you a denser and cooler air/fuel mixture and equalizing the exhaust port flow by eliminating turbulence in the 2 center exhaust ports. Back Cutting Valves Stock valves restrict the air flow into and out of the head. Back cutting the valves 28 to 30 degrees is a huge bang for the buck on any Buick, big or small block. Back cutting will enhance low and mid lift flow numbers. Intake Port Matching Ideally, intake manifold port openings and cylinder head port openings should match perfectly. Match porting will help achieve this. One thing to remember, a perfect match is almost impossible to attain, so it is better that the intake manifold openings be slightly smaller than the cylinder head port openings. UNDER NO CIRCUMSTANCES do you want the intake port opening larger than the head port. This will cause turbulence and reduce air flow, thereby hampering performance. Exhaust Port Matching If using stock exhaust manifolds, match porting the head exhaust openings to the exhaust manifold openings will benefit performance. DO NOT enlarge the exhaust port flange on a Stage 1 head. The manifold needs to be larger than the head port to prevent or reduce exhaust gas reversion. Unshrouding Valves in Combustion Chambers If you install Stage 1 valves in a standard small valve head, you MUST relieve the combustion chambers around the valves. If you do not, you will most likely not increase airflow or horsepower. In fact, air flow reduction may occur. Polishing Combustion Chambers This is beneficial not only for race engines, but for street driven engines too. Polishing will remove sharp edges that could cause hot spots in the chamber and result in early detonation. I can't remember where I found the information above, so maybe someone can correct anything if it's wrong.
The heads, crank, rods, intake, timming cover, balancer, pullys, cam, and anything elese except the pistons are compadible with eachother. The lifter and pushrods are different and if you want to use the 430 rockers on a 455 you need special pushrods, but other than that there the same.
Hi, just agreeing with the rest. The 430 heads will bolt straight on, the advantage is that the chambers are a smaller capacity, so by fitting 430 heads to a 455 you will raise the compression ratio without skimming anything. If you put later 455 heads on a 430 youwill get lower compression(not many people do that, but it might be useful if anyone was going to fit a supercharger to their 430 engine) cheers Louis
