Found a set of #3991492 heads on a local online board which Mortec shows as being 1970 camel humps with 2.02 valves 64cc chambers with acc. holes will these work better then my current heads which are 624's 76 cc chambers and i believe 1.94 valves . If they are not going to be an improvement how would they be on a 383 stroker that i'm planning for down the road or should i spend the extra for a set of Darts .I know the camel hump heads are old tech. but i'm planning the 383 to be a strickly street motor probably 325hp range mild cam with high torque
any opinions thanx

They are good factory heads, but if they need any work at all, you should consider an aftermarket head. Also they did not necessarily come with the larger valves. Head work adds up pretty quick.

I run 492's on my 388 and they're fine. Is there better head out there though, sure. How much they asking for them? They will bump your compression and they flow better then what you have now so it will be a definitly be a improvement. I guess it depends on the price.

They should be a good improvement on a 307. With '624' heads and 76cc Chambers, your compression ratio is likely 7.8-8.0:1. If nothing else, those should put you closer to 9:1.

EDIT: Not sure if there will be bore interference issues with a 2.02 valve and 3.875 bore... maybe someone else can comment.

A dandy head is the 305HO, -601 b/c of hardened seats, 1.84"/1.50" valves and chambers 58 cc's AND smaller!! It will keep your CR. up there...

Mine measured 55 cc's and slightly smaller which supprised me as well as about 160 cc intake ports!!!

I'm gonna install them on my 283 motor b/c I'm shooting for about 9.75 to 1 CR. using the .015" thick shim headgaskets...

pdq67

A dandy head is the 305HO, -601 b/c of hardened seats, 1.84"/1.50" valves and chambers 58 cc's AND smaller!! It will keep your CR. up there...

Mine measured 55 cc's and slightly smaller which supprised me as well as about 160 cc intake ports!!!

I'm gonna install them on my 283 motor b/c I'm shooting for about 9.75 to 1 CR. using the .015" thick shim headgaskets...

pdq67

I was also wondering about any issues with the 2.02 valves and the small 3.875 bore. I havn't physically seen the heads to find out what they would need but i agree if they need machine work they would be too costly unless i steal them

pdq67 i have thought about the 305 heads but i'm looking at building a 383 down the road , would the 305 heads work o.k on a 383

if you put those 305 heads on a 383 you might have trouble with the valves hitting the block deck because the 305's valves were made for the 305 cylinder bore which has about a 3 3/4" bore.the 350 block has a 4" bore.also,you will probably get more compression than you can run on pump gas since the longer stroke of the 383 combined with the small chambers on the 305's will both increase compression.plus,the 305's won't flow enough to feed the hungry 383.it likes to drink and breathe more fuel and air than the 305's can produce.

graemlins/clonk.gif what i meant was you might have valve-to-block contact when using 350 heads on a 305 block.

I ran 2.02s on a 283 years ago with no problem. But I would double check as it maybe getting pretty tight. Another option is a vortec head. They come with a 1.94 valve (should work with the 307 bore) and later should be a decent match for a 383. I would think they would also work better on your 307 than your current head.

Even if the 2.02's clear everything without contact, they will definitely be flow shrouded on the small bore size. I've always thought that for that bore size the 1.94 intakes are about as big as is good for performance. As mentioned already, check those heads for actual valve size. I too have seen heads that the charts list with 2.02 intakes, only to find 1.94's in place.

Thomas