12 replies to this topic

[lakeside]

Can someone please tell me what these heads are? I looked on google pictures and can't find them, blind maybe.

[TOERUNNER]

the casting number under the rocker covers will help to identify them,i can't find those casting marks either

[yel327]

If they are GMH heads they'll be 3932441 which are a 75cc head off a HT-HG GTS350 auto, 1.94/1.5 valves.

 

Could also be 3970126 or 3998920.

 

By the look of them the cast mark isn't machined so probably a Tonawanda head if they are HT-HG 441 head, but could also be a GM of Canada head if one of the other two.

 

On a flat top 350 these work out about 9.0:1 compression for the 441. Dish tops about 8.5:1.

 

As Rodney says have a look under the rocker covers for the cast number. In the centre it will have CANADA or MADE IN CANADA, a big T or nothing. The Canadian heads are obvious, the T is Tonawanda and nothing is a Saginaw casting machined at the Flint V8 plant in Michigan.

 

If they turn out to be standard Tonawanda 441 heads and you decide to replace them with something higher performance let me know. I'm trying to collect at least one of each HK-HQ SBC head to get some accurate CC results. I bought a pair of 441 heads off Ebay a few weeks ago for $30, thought they were Tonawanda but the big 7 looked like a T and they turned out to be Flint heads. They should be the same as the Tonawanda ones but need to be sure. So far I have: 

 

HK-HT 307

HK GTS327 Tonawanda

HT-HG GTS350 auto (but Flint not Tonawanda).

HQ late 993.

 

So i'm missing HT-HG manual 041, HG McKinnon 370, HK McKinnon 188 and some early HQ heads although these HQ are easy to find. The 370 head will be the biggest challenge. I have access to a 188 head but it has had bigger valves put in it.

Edited by yel327, 18 December 2015 - 09:12 AM.

[unclefestal34s]

just by the markings and accessory bolt holes i'm pretty sure there cast numbered 3998993 common 350 head cylinder also used in the later HQ 350 statesman and monaro's low comp head...

[yel327]

They don't look like 993's to me, those are normally something like a back to front L with the upright sides tapered like they'd eventually meet at a point if they didn't stop. They could be but look more like a rectangle to me which is 441, 126 or 920.

 

I just went and looked at my Flint 441's and it looks slightly different, but might be as the cast mark on the Flint heads is machines whereas these look like Tonawanda with the naked raw cast mark.

 

The 487 and 993's (same cast mark) I have are right at the back and at the bottom of the head pile so can't get to them right now to compare and get a photo.

[lakeside]

Here the cast number

[lakeside]

[LS1LX]

They look like door stoppers to me

[yel327]

What does the number say. Awful hard to read. They aren't 441's though. Is it 993 as Unclefestas says?

[lakeside]

The numbers are 3888336 c2417

[yel327]

3986336? Any heads with 38 at the start are pre 1968 which these aren't. Date code is C241 I think, the 7 is probably the fake machine screw next to the casting date.

 

I think these are 1972 L48 heads, possibly also used on 1971 L65. They are 76cc, 1.94/1.5 valve. Give 9:1 compression with flat tops or 8.5:1 with factory dish tops.

[lakeside]

How do you read the date codes? Could they be 336 X heads, the X would be behind the valve spring?

I spoke to my mate who I bought the engine off and thinks they pre 1970 heads. The block is a 4bolt 3932388 that is a 67-69 block,

[yel327]

C241, 24/3/71. I think the X heads are the flame hardened heads for ULP but don't quote me on that, 3/71 might be fractionally early for it.