I have a similar post in the wrong spot here on the H.A.M.B. Sorry just learning my way around. I'm building a 52 Studebaker Commander 2 door hard top and transforming it into a bullet nose. I plan to use a 454 and the one I'm getting on saturday is out of a 85 suburban. My questions are, What is the difference in a truck version and a.... not truck version. This motor has high flow rect. port heads and I'm wondering if they are factory ? Also is this engine suitable for my application or if not why? Thanks in advance for your help, Dean.
Suburbans did not come from the factory with high flow rectangular port heads. They had different configurations of oval port heads depending on the year and application. Frank
Thanks Frank, So they were added later. I'm confused on this site, I post this and then can't find it??? Are Truck engines different? Dean.
Make sure you are getting what you are paying for. Chances are that the heads might be the bigger oval ports, not the peanut oval ports, but high flowing rectangular ones...doubt it. Some guys will say that just to get some extra bucks out of someone who has no idea what they are buying. Look at it close and make sure you are getting what they say they are selling. The truck engines can have heavy duty rotating assemblies in them, and usually have a differant cam grind, one more for torque/pulling power compared to pass car or high perf stuff. They really are not much different basically. You can use virtually everything from a truck engine for a build...just swap a better cam, intake, and carb. If it has the small peanut oval port heads, then I'd at least put on the bigger oval port ones. No need for rectangular...unless it really does have them, and or you really plan on building a beast.
I love big block chevs, but why are you buying this ? Do you plan on going racing or using it to pull a camper ? The reason I ask is parts are more expensive, it takes a bit more engineering to make fit. You need to think about your steering and how the exhaust are going to be run, plus the extra weight on the front. A sbc could be a better choice depending on your plans for the car.
To answer your question about truck engines, if it is a pickup or suburban block there are little differences internally. Half Evil touched upon the things you might see. If it is a true truck engine though (slated for medium and heavy duty trucks, not pickups) then there are many differences like raised decks, different water pump, etc. Looks like you don't have that style. I would think that the biggest difference from stock is that your 454 is no longer sporting the stock heads as I am not aware any truck or suburban ever came with rectangular ports. BTW, rectangular ports have sooo much port volume that they are quite lazy below 3000 rpm. I speak from experience on this. Unless you are building a real screamer engine the oval ports are far better for street use. That being written, I am sure someone will pipe up that they are successfully running rect ports on the street.
>>>>,since someone could have changed the whole motor over the last 20 sum years ,,,get the block casting number off of the block behind the drivers side valve cover ,,,then ,,pull a valve cover and write down the head casting number ,,go to .. www.mortec.com ,,,click on big block casting numbers and check it all out ,,that's the best source for casting number info,, in '85 ,,there was several vatiations of 454 in trucks ,,some were 4 bolt main ,,some were 2 bolt ,,none had rect port heads tho ,,
Thanks for all the good input. I'm getting this engine and a rebuilt turbo 400 for free so I'm not going to be too picky. I'll check all the #'s and post again after I get her home. It is starting to sound like this is not the original engine for this truck. And to add yes I plan on building a real screamer. Really appreciate all the input!
Well that makes that engine an excellent choice ! Like was said get it home, pull the numbers and check and see what you have.
Got er home and sunday pulled it apart, Found a four bolt main and rect. port heads that say Hi Perf. under the valve covers. Still haven't taken the time to write down the #'s yet but I think I know what I need to know now. Sure enough it came with a freshly rebuilr turbo 400 trans and the top half of the engine has been rebuilt. Currently trying to find out what pistons and cam were used. Only bad thing I've found is a fair amount of rust in the water jacket and looks like I should replace the harmonic balancer. I think this is the deal of my cars lifetime!!! Dean.
the HI PERF on the head doesnt mean its "high performance", all factory heads came with that stamped on it. also, more often than not people mistaken the oval ports for rectangle port heads. the only way to know what you have is to reference part #'s.
no.. only the rec port heads had hi perf on it sounds like some one slipped a 396 /427 motor in that burban ..a 4 bolt block? if its a 396/427 that block is worth 1500 to 2000 by itself the heads are worth less to you for a street driver id run a nice set of close chamber oval ports i picked up a 396 375 hp bbc that had a 4 bolt block and rec heads on it parted it out and made some good money off it . if i were you id sell that set up and take the money and build what you really want .
BBC Gasser is right.I would part it out and make sum bucks for another motor.Putting a 4 bolt main BBC in a street car is a waste ,and that block is worth big bucks to a racer or restorer if its a 427 .Factory rectangular port heads are pretty scarce nowdays.I'd check the #'s on the block and heads for sure.Maybe you will get lucky and find they came from a 70 LS6 Chevelle ...
Not sure exactly where to look but here is what I came up with, On the block it clearly sats 7.4LG HI Perf., K2 PA 88 / (40)5445. the first is on the right/left side and the second on the rear just above where the bell housing would bolt on. On the heads inside the valve covers, GM 1T8272990 My eyesight isn't the greatest so hopefully these #'s are right. What do you guys think??? Dean.
More than likely 6272990 , 70 and up rectangular port heads whats the casting number on the back of the block by the bellhousing
Does the (40)5445 sound right? If not can you give me some idea what it should be+/- I'm pretty sure its an 85 out of a 3/4 ton Suburban. Dean.
Since it has 7.4 that means 7.4 liters, as in a newer style block. Probably a Mk V block, but check the casting date. To use earlier heads on the Mk V block you need special head gaskets I think? I know there is some water passage that will leak if you use Mk IV gaskets.
im not 100% sure... its been awhile... but my oval ports from a '68 396 had HI-PERF cast into them. it was a 325 hp job from an impala.
I hope this isn't true. I'm using 66 ,(702) heads off of a 427 on my 85 7.4 block. I've only broken in the cam, but there doesn't seem to be any water in my oil.
When did the BBCs change over to Mk V? I think it was not until like 1991. So your 1985 engine is the old Mk IV style, and not a problem. I am not sure on the head gasket question, can someone give better details? I have only messed with the older Mk IV style engines far as swapping heads. Or maybe it is using newer heads on an older engine?
Your motor sounds like a gm crate replacement 425 hp 454 of a late model vintage. As far as head swapping goes, its early heads on late is okay. Its the late heads with the bigger water passages that need a different head gaskit on early blocks.
The heads I have are 6272990 and they do need the special intake gaskets due to two openings, one on each side of the middle water jacket port. Went to napa to get them and they cant even tell me which ones I need. Plus any rect. port gaskets have to be ordered from their hub in Chicago (geeez)