sb heads?

[blake22]

okay im 15 and i have a 78, an 81z and a caprice for a motor.
we just got the caprice today and im wondering about heads.

are all small block heads the same? as far as valve covers go? because for some reason im thinking that like the late 60s small blocks had smaller valve covers. or is that just a 283? im just confused and wanting to get some chrome valve covers for my 350. haha so any help would be awesome.
thanks, blake

 

[Cardinal]

There are basically three different valve covers for small block Chevys (not counting the "new" engines). Stagger hole valve covers used on all SBCs from 1955 to about 1960 or so. Then there are the "square" bolt pattern valve covers used till the late 1980's. Lastly there are the center bolt valve covers used on late 1980's to early in this century.

What year is the Caprice? Do you know exactly which engine it has in it? It could be any of the following SBCs: 262, 267, 305 or 350. If it's any off the first three, the heads are most likely junk. IF it happens to be a 350 the heads on it are probably the same ones on your Camaro.

As for heads there are four generations of them. 1955 to 1968 had no accesory holes in the ends of the heads (for the alternator and AC). 1969 to he early 1990's have the accessory holes. 1990's to the turn of the century are Vortec (center bolt valve cover) heads.

The best advice I can give you is to make a friend of someone who has sucessfully built numerous small block Chevys. Also buy the book "How to Hot Rod Small-Block Chevys" http://www.summitracing.com/parts/HPB-HP8/ for starters. It has a ton of good information in it too.

 

[pdq67]

Here you go.

The real early 265 and 283 SB valve covers had staggered bolt-holes. Top two are not in line, (narrower spaced), w/ the bottom two here. I want to say up to '59???

Then all the rest are the same up until the center-bolt valve covers.

Now, engines. All the engines up through '85 have 2-piece crank flange seals, (again, up through '59 or so, rope crank seals), '86 and after, they are 1-piece.

And somewhere in here, ('86 and on?), the 4 center intake bolts angles got changed. We just ream the intake manifold out and use little wedges to re-align the bolts back to the older head angle.

Next, the early '90's LT1's are top to bottom cooled so their heads can't be used on the older engines. You tell the LT1's b/c their water pumps are driven off the camshaft internally, no water pump belt here.

And finally the Vortec heads w/ their taller intake ports need center valve covers, guided rockers and a dedicated intake manifold, but they do fit everything except the LT1's.

pdq67

PS., Oh, the tri-5 engines don't have any side mount bolt bosses b/c they were mounted in two spots in the front and on both sides of the bell housing. (That's what the four unused bolt-holes are for on the front wall down low on each side.

 

[Cardinal]

Eric69: 98% of what you said is true except the eary 265 and 283s had stagger hole valve covers which will not fit the rest of the heads. Those early heads had small combusiton chambers, small valves, and no accessory holes in them either. The only picture I could find of the stagger hole valve covers was on Ebay: http://cgi.ebay.com/ebaymotors/CHEV...ies?hash=item4399eea7b8&_trksid=p4506.c0.m245 Notice how the intake side of the valve cover bolt holes are not aligned with the exhaust side? Hence, the name "stagger hole" was given to them.

 

[pdq67]

Talk about small ported heads, my '56, 265, -306 sparkplug trough heads cc's intake port of 118 and 120 ccs!!

This is why the some later 283 powerpack heads at 137 to maybe 140 cc's made the old 283 power pack engines run like "scalded-dogs"....

Then the -461 and -461x Double hump heads came out that are 158 to 160 and 165 to 170 cc ported.

This made the 327's run WAY BETTER!!!! To this day, a 365hp/327 is an engine to be reckoned w/!!

pdq67

 

[blake22]

okay that helps alot. we think its a 350 but where not sure yet. thats what im wanting haha. the sticker says 305 but i dont wanna 305 so im just going to say is a 350. hahaha
so anyways, the caprice is a 87. some reason i was thinking that vortec's didnt start untill the 90's thow. but im probly wrong. you guys know allooott more. haha.

so if i went to auto zone or somewhere like that the valve covers they have would be the right ones? its the ones with the bolts on top or? i was thinking they where on the side thow?

 

[Simon@London]

okay that helps alot. we think its a 350 but where not sure yet. thats what im wanting haha. the sticker says 305 but i dont wanna 305 so im just going to say is a 350. hahaha
so anyways, the caprice is a 87. some reason i was thinking that vortec's didnt start untill the 90's thow. but im probly wrong. you guys know allooott more. haha.

so if i went to auto zone or somewhere like that the valve covers they have would be the right ones? its the ones with the bolts on top or? i was thinking they where on the side thow?

Make sure, there will be four perimeter bolts holding the covers around the outside or, 4 bolts down the middle of the cover called centerbolts.

It's likely a common 305 which can be tricked out a little to make more power.

According to GM that should be the LG4 sbc engine.

After 1996, its usage was limited to light trucks and SUVs as the Vortec 5000.

That model engine is probably this one.

1987-88 5.0 L/305 cu in LG4 Small-Block V8 170 hp

 

[AJ_72]

That model engine is probably this one.

1987-88 5.0 L/305 cu in LG4 Small-Block V8 170 hp

That's correct according to this site. Evidently (which I'd have never known), that was the only V-8 offered in the 1987 Caprice, Coupe, Sedan or Wagon.

http://www.capriceclassic.com/onamarie.geo/chevy1987.html

 

[MrZeal]

I took the motor out of a Caprice a couple of years ago. Threw the block away and ported the heads to use on a 350. Built lots of torque and power by upping the CR with the 305 heads. Even if you do not want the 305, keep the heads and work them or sell them on Craigslist.

 

[blake22]

from what i can see there is 4 bolts down the middle. so its a vortec?

i have another question too.. can i use any 4bbl carb?