I just bought a 89 suburban with a 454 in it. I am going to pull it soon(a couple of months) and put it in my 1971 camaro. Before putting it in the car I want to boost it a bit. I'm told that it may have the peanut port heads on it. If that is the case would I be better off finding some other heads to put on it? I would rather pick up some heads that I can find somewhat cheap that will bolt right on and raise the compression a bit. What casting # heads will acomplish this? I'd like to spend $400 or so on the heads. Am I dreaming?

When doing that I might as well change the cam too, right? Which cam would go well with my head change? The car is a four speed and will have headers with a performer intake. Thanks for your help. I have read through alot of the threads on here looking for info. Thanks for the help.....Kevin

judge692,,
welcome to the board.
you'll need the counterweighted stick shift flywheel for the 454 also. it's externally balanced.

maybe go to www.mortec.com for bbc head casting numbers and cc's. it'll give you casting #'s and year range's to look for as well. the older 396 closed chamber heads arround 96cc-100cc are what you're looking for.

the smaller peanut ports aren't very good if you're intending to turn this thing over 4500rpm. although they make great low end torque heads if you set the engine up that way. like for towing.

400$,, doubtful,, probably quite a bit more after you have a valve job,, and guide work,, and hardened seats installed,, hardened exaust valves made for hardened seats,, and bigger springs set up on them. plus the initial core cost. those are 35-40 year old heads. expect to do some guide work on them as well as being sure they have hardened exaust seats/hardened valves installed for use with unleaded fuel. you'll be lucky to get the head cores for 300-400$. search arround and you might get lucky somewhere though.

with a flat top piston,, some of the fully closed chamber 396 large ovals would get you arround or a little above 9.5:1 with an undecked block and a replacement .022-.026 steel shim thin gasket. using the .040 thick rebuilder type gaskets or composition type gaskets will loose some compression and quench distance with an undecked block.

be sure to keep your piston to head clearance (deck height + gasket thickness) under .050 to work the best. something like a 268he or 270magnum from comp cams or the equivilant would work ok with the larger oval port heads and 9.5 or so compression. don't forget to get the matching springs for the cam though. you'll need them. that will perk it up quite a bit. a performer intake with a 3310 holley 750 vacuum secondary carb and some 1 3/4" long tube headers works well with that too.

hope it's not a saginaw 4 spd. the torque rating on those isn't very high. i busted 8-10 of them with a decent small block at anything over 4000rpms on a clutch sidestep. finally went automatic with a decent converter and all that stopped. good luck. keep up posted.

Muncie M-20. Thanks for the flywheel info. What would the cc be on the heads I have now assuming they are the stock ones 115-120 ? Those close chambered heads won't make more compression than that huh. Hmmm sounds about where I want to be. Any use in maybe keeping the heads for economy sake and maybe shrinking the head gasket thickness for more comp. Are these peanut port heads totally worthless? Thanks for your input ...Kevin

Anyone else have any thoughts on this stuff.

I think that's a mark V engine, and if so the older mark IV heads have coolant passage location compatibility issues. You should look into that before spending $$$ on heads.

I think that's a mark V engine, and if so the older mark IV heads have coolant passage location compatibility issues. You should look into that before spending $$$ on heads.

Didnt start Gen V untill 91.

Don't the vortec heads have small chambers and big oval ports? I heard they were a good alternative for the 65-66 396 head.

Didnt start Gen V untill 91.

My bad, thanks for the correction. :)

Don't the vortec heads have small chambers and big oval ports? I heard they were a good alternative for the 65-66 396 head.

i think so,, iirc,, the ones in the 366 truck heads till 1990. but they have oddball sized valves in them. something like 1.660 or 1.680 in the exaust. can't remember the intake sizes. but they were available in that smaller chamber for the 366 truck like you say. might have to do some pocket enlargement bigtime. small valves in them for the smaller bore engine of the 366.

i think all the 454's in that era were normal 2.06/1.72 valves with larger chambers. ditto on the mark v. think it was 91 when that one piece rear seal block started for the bbc. hope it helps.

Would putting a 454 into a 2nd gen make it more nose heavy
kinda like the early vettes. Would it be a good idea for a daily driver.
Would it twist the body more at a hard launch?? I would not mind doing the
same, but with a 6/speed. :bowtie: I still want the car to handle well.

Would putting a 454 into a 2nd gen make it more nose heavy
Yes. Iron head BB is 210 lbs heavier than an alm head sb.

kinda like the early vettes. Would it be a good idea for a daily driver.
Yes. More cubic inches per dollar spent is always desirable.

Would it twist the body more at a hard launch?? I would not mind doing the
same, but with a 6/speed. :bowtie: I still want the car to handle well.
Yes but $20 in 2"x2" tubing welded into the right spot will make it better to 11.5
And handling, blah, blah, blah.
:)

74Rat, what would be wrong with an open chamber 118 cc head. Yeah it won't bump the comp. ratio much, but isn't an open chamber better for performance?

Welcome to the board judge692


Chris

74Rat, what would be wrong with an open chamber 118 cc head. Yeah it won't bump the comp. ratio much, but isn't an open chamber better for performance?

Welcome to the board judge692


Chris

generally,, a smaller compact chamber is a faster burning chamber when compared to a larger one. with a fast burn chamber,, less timing lead is needed,, therefore less negative work is done on the compression stroke if the spark happens closer to tdc. the more degrees you light it before tdc means it's building pressure starting at 36* before tdc instead of say 32* before tdc. you save 4* of negative work on each pistons compression cycle. like free energy. ok,, maybe the only free energy is after the purchase price of the fast burn heads!!

a dome sticking up in the flame travel path will slow the burn speed having to negotiate up and over/arround the dome,, requiring more timing lead. with bbc, it requires ALOT of cubic inches to be able to use a flat top piston to get 10.0:1 and up compression ratios with no dome in there,, with a 119cc head. so most 454 based engines have some kind of dome to get there. hope it helps.

74RAT,

BB 1.84"/1.94" intakes and 1.66" exhausts Truck heads!! Actually they are large ovals so all that needs to be done is ream them out and install bigger valves in them..

pdq67

74RAT, you are a gold mine of information. I see a pm headed your way for just a tad more info......lol



Chris

74RAT,

BB 1.84"/1.94" intakes and 1.66" exhausts Truck heads!! Actually they are large ovals so all that needs to be done is ream them out and install bigger valves in them..

pdq67

thanks pdq,, couldn't remember. been a while since i've seen those. see some burned exaust valves with them,, and ordered more of those in the past. not many intake valve problems with them.


402z28,, i can't take all the credit,, it really takes ALL of us here to become ONE with all the info. everyone really helps everyone here. that's what really makes it happen. we all pool our experiences together to become a larger knowledge base of info. we all get told/corrected occasionally too!! he he, ha ha. everyone has their area of knowledge,, some different than others,, but together we are huge!!

These are the heads I was talking about.
http://www.sdpc2000.com/catalog/281/products/215/Bare-L29-Vortec-BB-Chevrolet-Cast-Iron-Cylinder-Heads.htm
Should be able to find them used with a bit of looking. I have heard they have good flow numbers and should wake up a truck motor.

definately 80'427,,, looks like them. they used those in school buses too. maybe hit up your local independent school district repair yard to see if they have some laying arround waiting on warranty or scrapped or something. you might get lucky. hope it helps.

Fwiw, the newer L-29 BB heads were designed to replace the Peanut Port heads!

The PP heads only have about 200 cc intake port's and 118 cc open chambers whereas the L-29 heads have about 230 cc intake ports and 100 cc heart-shaped fast burn chambers even though GM calls them a large oval..

A true large oval is like 255/262 or so cc........... And can have chambers anywhere from 96.+ closed to 122 cc's open

pdq67

Will these heads fit my 1989 454? Thanks, Kevin
http://cgi.ebay.com/ebaymotors/vortec-7400-454-big-block-chevy-heads-marine-truck_W0QQitemZ170078156071QQihZ007QQcategoryZ33617QQrdZ1QQcmdZViewItem

Will these heads fit my 1989 454? Thanks, Kevin
http://cgi.ebay.com/ebaymotors/vortec-7400-454-big-block-chevy-heads-marine-truck_W0QQitemZ170078156071QQihZ007QQcategoryZ33617QQrdZ1QQcmdZViewItem






according to the add, It states that they will not..."will not work on pre 90 mk 4 motors"





Chris

yeah,, says 91 and up. i see that now. oops.

seems i remember that there was a company a number of years back that was marketing a gasket that would use some kind of a slip in piece that covered the water jackets in the "right" places. they say it worked,, don't know if i'd trust it though. i've always matched up the gen series myself. maybe pdq has some background on those gaskets.